WO2014133432A1

WO2014133432A1 - Gravity-train system

Info

Publication number: WO2014133432A1
Application number: PCT/SE2014/000002
Authority: WO
Inventors: Lifeng Wang
Original assignee: Lifeng Wang
Priority date: 2013-03-01
Filing date: 2014-01-09
Publication date: 2014-09-04
Also published as: CN104015735B; CN104015735A

Abstract

This invention discloses a gravity-train system, in which the train gravity is used as main source of driving force for train accelerating and braking, and a method of its operation. The system includes gravity-train 1 and gravity-train tracks. The gravity-train 1 includes gravity-train carriages 15 which with adjustable floor 28 can run on long and steep tracks, and the running-resistance balancing engine which with small power consumption balances the running resistance. The gravity-train tracks include long steep downhill tracks 3, long steep uphill tracks 5, intermediate pathway tracks 4, station tracks 2 and possibly gravitational start tracks 11, wherein the horizontal plane through the lowest point of the intermediate pathway tracks 4 is taken as the reference plane 33, above which the top 9 of the long steep downhill tracks 3 and the top 10 of the long steep uphill tracks 5 are essentially at the same height. The driving force for acceleration of the gravity-train 1 is obtained mainly upon the gravity to do positive work by transforming the gravitational potential into kinetic energy, while the gravity-train 1 deceleration to break is achieved mainly upon the gravity to do negative work by transforming the kinetic energy into gravitational potential, thus saving a lot of energy consumption.

Description

GRAVITY-TRAIN SYSTEM

Technical Field This invention relates to the field of train technology, particularly to a gravity-train system, in which the gravity is used as its main source of driving force for train accelerating and braking, and its operation method thereof.

Background Art

When running, a train advances at an uniform speed if its forward driving force is equal to the running-resistance, and acceleratedly if the driving force is greater than the running-resistance. This part of the force driving the train to advance acceleratedly is termed as the train's accelerating force.

The running-resistance of a train includes basic resistances (such as bearing resistance, rolling resistance, sliding resistance, shock and vibration resistance, air resistance, etc.) and additional resistances (such as running on curved rails, in tunnels, etc.). Research has shown that, when a train runs at an uniform speed of 70km/h, the basic unit resistance is 5.1N kN. It is also reported that, according to the theoretical calculations based on the running resistance formula of subway trains, the unit running-resistance is 4-5 kg t for the train speed of 70 km/h, in agreement with the actually measured result. It means that, in a normal case without any additional resistance, the driving force for a train to balance its running-resistance is about five thousandths of its weight. The train's accelerating force F is known according to the Newton's second law as F = ma, where m is the train mass, a is the train acceleration. Also taking the subway as an example, the train acceleration is about 1.0m/s² when running acceleratedly. The train's accelerating force is about one-tenth of its weight, usually much greater than the driving force to balance its running-resistance. To save train's accelerating force is one of the key factors for the train energy saving. It has been nearly two hundred years since 1814 when Englishman George Stephenson invented a steam locomotive, or 150 years since 1863 when opened the world's first underground railway, London's Metropolitan Railway, that the train engines (such as steam engines, internal combustion engines, electric motors, linear motors, etc.) have been always the main driving force for train accelerating, and that from the energy point of view the train acceleration has been mainly made by transforming the thermal, chemical, or electrical energies into kinetic energy.

Since the era of horse-drawn carriages, mankind has known that the downslope benefits the acceleration of the vehicles. This common sense has been long reflected also in building the subway tracks, called accelerating ramp (or energy-saving ramp), meaning that some of the stations are located slightly higher where a leaving train runs through a short downslope section before entering its ordinary journey to save part of the energy from the train engine used for its accelerating. For example, a rather authoritative design of accelerating ramp is that, out of the departure end of the station there is

l a 250 m long ramp with a gradient of -22~-26 %o, which can reduce 20-25% of the electrical energy consumption for the train engine to continue pulling the train to reach a target speed of 80km/h. It represents a model of the existing accelerating ramp technology, and has almost reached the upper limit of the existing accelerating ramp energy-saving efficiency. The causes limiting the further improvement in energy-saving efficiency of the existing accelerating ramp relate to some of the existing technological problems as described below:

1. The gradient of the existing accelerating ramp is small. In the case shown above, the component force of gravity in the direction of -22'— 26 %o gradient can produce acceleration about 0.21- 0.25m/s², while about 0.99 m/s² is needed to reach a target speed 80km/h after the train has run through an accelerating ramp of 250 m. There the existing accelerating ramp can only produce a small fraction of the acceleration needed, and so reduce a small part of the energy consumption, such as 20-25%.

2. The floor of a traditional subway train carriage is fixed (with its chassis and/or walls). Therefore, the carriage floor is always parallel to the tracks during train travelling. A larger gradient of the tracks may make the passengers lean forward or backward, feeling uncomfortable and unsteady.

Thus, the conventional technologies have got a strict restriction to the track gradient, such as a maximum of 30 %o.

3. The length of the existing accelerating ramp is short. The length of an existing accelerating ramp is generally 200-300 m, the component force of gravity in the direction of accelerating ramp acts to the train in a shorter distance, thus doing less work. The short ramp with a small gradient and small change in railway elevation make very limited the transformation of the gravitational potential energy into kinetic energy through the entire existing accelerating ramp.

4. In the prior art design specifications, the train engine is the main source of driving force for train accelerating. The existing train accelerating has still mainly consumed a large amount of other energy being transformed into kinetic energy, while the transformation from the gravitational potential energy into kinetic energy accounts only for its very small part with the accelerating ramp playing only a supporting role. In the prior art design specifications, the train engine as the main source of driving force for train accelerating has also limited the length of accelerating ramp, for example, under the same condition of accelerating ramp gradient of -30 %o, the computer simulation experiments of an existing train model have shown that an accelerating ramp of 400 m saves energy by 5-8% less than that of 300 m does. Therefore the length of an existing accelerating ramp in general does not exceed 200-300 m.

As pointed out by research reports, in the prior art, the section with the largest part of energy consumption of a subway train during travelling is that of the outbound accelerating ramp, which is also the focus of calculations of energy consumption in simulated comparisons. - That the section of the existing accelerating ramp is the one with the largest part of energy consumption has shown that the energy saving of the existing accelerating ramp itself is limited on one hand, and on the other hand revealed that the conventional train engine as the main source of driving force for train accelerating consumes a large amount of energy, which should be taken as one of the key entry points in the research subject of train energy saving.

The train braking is a process in which the braking force takes away the train's kinetic energy. The existing train braking mainly uses mechanical friction or electromagnetic force to takes away the train's kinetic energy, transforming it into heat (dissipation) or electricity (reservoir). The main approaches of braking include: brake shoe brake, disc brake, magnetic track brake, track eddy current brake, rotating eddy current brake, resistor brake, regenerative brake, hydraulic brake, and reverse steam brake among others. In the existing technology, mechanical friction, electromagnetic force, etc. are the main sources of the force for train braking, reflected in a variety of the above conventional approaches of braking. As an auxiliary way, at the inbound ports of some stations there sets a decelerating ramp (also known as energy-saving ramp), a short length of upslope ramp with a small gradient for the train to run through before entering the station, where a small part of kinetic energy of the train is transformed into gravitational potential energy to slightly reduce the train speed, saving a small part of the energy consumption of braking. The reason why the existing decelerating ramp can only transform a small part of the train kinetic energy into a limited part of gravitational potential energy is because the gradient of the existing decelerating ramp is small (less than 30 %o), because its length is short (200-300 m), and because the change in the elevation of the existing decelerating ramp is small, which is essentially related with the existing technological issues, such as the conventional train structures, the track railway design specifications, and the conventional approaches of braking, basically the same as analysed above on the existing accelerating ramp, and taken for the reference.

Contents of the Invention

(1) Technical problem to be solved

The technical problem to be solved is to provide a gravity-train system, in which the gravity is used as main source of driving force for train accelerating and braking, and a method thereof, so that the gravity-train accelerating has no longer need to use an engine as its main source of driving force which would consume a large amount of heat, chemical, electric or other energy, and so that the gravity-train braking has no longer need mainly to use the mechanical friction, electromagnetic force or other means which would rely on the conventional approaches of braking for deceleration to stop, thus saving energy for train travelling.

(2) Technical solutions

To solve the above mentioned problem, on the one hand, the invention provides a gravity-train system using the gravity as main source of driving force for the gravity-train accelerating and braking, which includes gravity-train and gravity-train tracks. The gravity-train includes:

Gravity-train carriages, a gravity-train has one or several gravity-train carriages which can run on the tracks with steep slope on a long ramp; and

Running-resistance balancing engine, to produce power for the gravity-train to balance the running- resistance excluding the resistance related to the tracks gradient during the gravity-train travelling on the whole gravity-train tracks.

The gravity-train tracks include:

Station tracks, including both ends at the outbound and inbound for the gravity-trains to start and stop; Long steep downhill tracks, top of which is connected to the outbound end of the present station tracks, with such a length and gradient as for the gravity-train upon its gravity to do positive work for acceleration running along the long steep downhill tracks to reach the target speed;

Long steep uphill tracks, top of which is connected to the inbound end of the next station tracks, with such a length and gradient as for the gravity-train upon its gravity to do negative work for deceleration breaking along the long steep uphill tracks to stop on the tracks at the next station;

Intermediate pathway tracks, which are connected between the bottom of the long steep downhill tracks and the bottom of the long steep uphill tracks, and which are set on a horizontal level or along a curve slightly lower at its middle with a gradient of ±2-3 %o to favour the subway drainage;

Among all mention above, the horizontal plane through the lowest point of the intermediate pathway tracks is taken as the reference plane, above which the top of the long steep downhill tracks and the top of the long steep uphill tracks are essentially at the same height.

Preferably, both of the long steep downhill and the long steep uphill tracks are smoothly connected to the station tracks and the intermediate pathway tracks. Preferably, part of the station tracks near their outbound end comprises a forward and downward slope, which can make the gravity of the gravity-train produce a gravitational component being in the direction of train-running but smaller than the absolute value of the running resistance, and on which the gravity-train can start by the running-resistance balancing engine power with assistance of such the gravitational component; or the part of the station tracks near their outbound end is configured as the gravitational start tracks, on which the gravity-train starts upon its gravity.

Preferably, the rear end of the gravitational start tracks, i.e. the one away from the long steep downhill tracks, is connected through a rotatable structure of pestle socket joints to the main part of the station tracks, while the fore end of the gravitational start tracks, i.e. the one toward the long steep downhill tracks, is set on a liftable facility; the gravitational start tracks can be situated on either of two operating positions: the first on a horizontal level, and the second with a forward and downward gradient; at the first operating position the fore end of the gravitational start tracks is located above the top of the long steep downhill tracks, at the second operating position the fore end of the gravitational start tracks is smoothly connected with the top of the long steep downhill tracks and in this case the gravity of the gravity-train on the gravitational start tracks produce a larger gravitational component in the direction of its running which is greater than the absolute value of the running resistance and makes the gravity-train to start upon its gravity.

Preferably, beneath the gravitational start tracks there are supports with a liftable supporting facility, which rising and falling makes the gravitational start tracks turn up and down around the rotatable structure of the pestle socket joints to switch the gravitational start tracks between the first and second operating positions.

Preferably, beneath the gravitational start tracks there are also some buffer facilities for shock absorption. Preferably, the gravity-train tracks can be set as underground lines, elevated lines, underground/elevated lines, surface/underground lines, and surface/elevated lines.

Preferably, a gravity-train carriage includes a carriage body, includes an adjustable floor flexibly connected to the carriage body, and /or safety seats with seat belts fixed to the carriage body or on the floor, and includes a control device adjusting the adjustable floor to a desirable levelness according to the gradient of the gravity-train tracks on which the gravity-train runs.

Preferably, the adjustable floor is connected to the carriage body via a horizontal axis in the middle of the adjustable floor, the axial of the horizontal axis is parallel to the carriage chassis and perpendicular to the direction of train travelling, and around the horizontal axis the adjustable floor can turn up and down accordingly.

Preferably, the gravity-train carriage also includes some sensors to measure the levelness of the train carriage and send the corresponding signals for the horizontal level to the control device.

Preferably, on the inner walls of the carriage body there is a set of snap-in facilities, which fixes the position limit of the adjustable floor at such a desired level degree after the control device adjustment upon the gravity-train running along the gravity-train tracks e.g. the long steep downhill or uphill tracks.

Preferably, the gravity-train tracks also includes the signal devices of gradient change near the positions where the gradient of the gravity-train tracks starts changing, to send the gradient change signal to the control device on the gravity-train carriage when the gravity-train is to enter the section of the gravity-train tracks with the gradient change.

On the other hand, this invention also provides a method of operating the gravity-train system, comprising the following steps:

SI: The gravity-train starts on the gravitational start tracks or on the forward and downward slope at the fore part of the station tracks simultaneously the running-resistance balancing engine ignites, the gravity-train exits the outbound end of the present station tracks and reaches the long steep downhill tracks;

S2: On the long steep downhill tracks the adjustable floor is located in the desired level degree adjusted by the control device; under the action of the gradient of the long steep downhill tracks, the gravity of the gravity-train generates a gravitational component for the gravity-train accelerating along the direction of its travelling with assistance of the running-resistance balancing engine power, making the gravity-train running acceleratedly to the intermediate pathway tracks to achieve the target speed;

S3: On the intermediate pathway tracks, the adjustable floor is parallel to the carriage chassis adjusted by the control device ; with the running-resistance balancing engine power the gravity-train runs uniformly at the target speed until it reaches the long steep uphill tracks; S4: The gravity-train runs onto the long steep uphill tracks with an initial velocity of the target speed and with the assistance of the running-resistance balancing engine power; the adjustable floor is located in the desired level degree adjusted by the control device ; under the action of the gradient of the long steep uphill tracks, the gravity of the gravity-train generates a gravitational component for the gravity-train decelerating along the direction of its travelling, making the gravity-train running deceleratedly until it reaches the inbound end of the next station tracks and the train speed approaches zero; On the next station tracks, the adjustable floor is parallel to the carriage chassis adjusted by the control device; the gravity-train stops simultaneously the running-resistance balancing engine turns off.

(3) Beneficial effects

According to the invention the gravity-train accelerating or braking depends mainly upon that its gravity does positive or negative work, that is, the gravitational potential energy is transformed into the kinetic energy or the kinetic energy is transformed into the gravitational potential energy.

According to the invention the gravity-train accelerating differs from that of the conventional train which accelerating depends mainly upon its engine consuming a large amount of heat, chemical or electrical energy to transform into kinetic energy. The gravity-train described in this invention does not need its engine as a main source of driving force for its accelerating, while the gravity-trains engine is the running-resistance balancing engine used only to balance the running-resistance unrelated to the tracks ramp gradient during travelling, clearly such running-resistance is much smaller than the driving force for accelerating, and so the running-resistance balancing engine only needs a smaller power and does less work than the conventional train engine. The gravity-train braking differs from the conventional trains as it needs no longer to depend mainly upon mechanical friction or electromagnetic force to consume energy to take away kinetic energy of the train.

According to the law of conservation of energy, gravitational potential energy and kinetic energy are interconvertible as mgh = ½ntv² where A stands for the height from the object with a gravitational potential energy to a reference level, m for the object mass, g for the gravitational acceleration, and v for the object velocity, the gravity-train carriage described in this invention using the adjustable floor to benefit its running on the long steep downhill tracks and the long steep uphill tracks with a larger gradient and a larger elevation-change makes higher energy transformation between gravitational potential energy and kinetic energy of the gravity-train possible during its accelerating and braking; among the gravity-train tracks on which the gravity-train runs with assistance of the running-resistance balancing engine power described in this invention, the top of the long steep downhill tracks and the top of the long steep uphill tracks are essentially at the same height above the reference plane through the lowest point of the intermediate pathway tracks, making the gravity as a main source of driving force for the gravity-train accelerating and braking, which is inexpensive, recyclable and reusable.

This invention makes the train running with a lot of energy saving. Brief Description of the Drawings

Fig 1 shows the schematic diagram of the gravity-train system according to an embodiment of the invention; Fig 2a shows the schematic diagram of the gravitational start tracks, at its first operating position, of the gravity-train system according to an embodiment of the invention;

Fig 2b shows the schematic diagram of the gravitational start tracks, at its second operating position, of the gravity-train system according to an embodiment of the invention;

Fig 2c shows the partially enlarged diagram of the location I in Fig 2b;

Fig 3 shows the schematic diagram of the horizontal level adjustment of the adjustable floor in a gravity-train carriage according to an embodiment of the invention;

Fig 4 shows the schematic diagram of a gravity-train carriage running along the long steep downhill tracks according to an embodiment of the invention; Fig 5 shows the schematic diagram of a gravity-train carriage running along the long steep uphill tracks according to an embodiment of the invention;

Fig 6 shows the schematic diagram of the gravity-train running along the gravity-train tracks according to an embodiment of the invention;

Wherein, 1: gravity-train; 2: station tracks; 3: long steep downhill tracks; 4: intermediate pathway tracks; 5: long steep uphill tracks; 6: gravity; 7: gravitational component for acceleration; 8: gravity component for decelerating; 9: top of long steep downhill tracks; 10: top of long steep uphill tracks; 11: gravitational start tracks; 12: pestle socket joint; 13: pestle; 14: socket; 15: gravity-train carriage; 16: fore end of gravitational start tracks; 17: liftable supporting facility; 18: connection; 19: buffer facility for shock absorption; 20: horizontal line; 21: carriage chassis; 22: horizontal axis; 23: front half of adjustable floor; 23 (a): front half of adjustable floor on the median level in parallel with carriage chassis; 23 (b): front half of adjustable floor adjusted to the horizontal level; 23 (c): front half of adjustable floor adjusted to a small gradient to maintain a comfortable ride; 24: bottom of long steep downhill tracks; 25: bottom of long steep uphill tracks; 26: adjustable supporting pillar; 27: adjustable supporting pillar; 28: adjustable floor; 28 (a): adjustable floor in the median plane in parallel with carriage chassis; 28 (b): slightly upturned front half of adjustable floor; 28 (c): slightly downturned front half of adjustable floor; 29: signal device of gradient change; 30: elevation angle; 31: depression angle; 32: snap-in facility; 33: reference plane; 34: height at the top of long steep downhill tracks; 35: height at the top of long steep uphill tracks.

Specific embodiments Hereinafter, this invention will be described in detailed embodiments referring to the drawings. Embodiment 1

As shown Figs 1-6, this embodiment describes the gravity-train system using the gravity as its main source of driving force for accelerating and braking, comprising the gravity-train 1 and the gravity- train tracks.

The gravity-train 1 comprises: - gravity-train carriages 15, a gravity-train 1 has one or several gravity-train carriages 15 which can run on the tracks with steep slope on a long ramp; and

- running-resistance balancing engine (not shown), to produce power for the gravity-train 1 to balance the running resistance excluding the resistance related to the tracks gradient during the gravity-train 1 travelling on the whole gravity-train tracks.

The gravity-train tracks comprise:

- station tracks 2, including both ends at the outbound and inbound for the gravity-trains 1 to start and stop;

- long steep downhill tracks 3, the top 9 of which is connected to the outbound end of the present station tracks 2, and the length and gradient of which are suitable for the gravity-train 1 upon its gravity doing positive work for acceleration running along the long steep downhill tracks 3 to reach the target speed;

long steep uphill tracks 5, the top 10 of which is connected to the inbound end of the next station tracks 2, and the length and gradient of which are suitable for the gravity-train 1 upon its gravity doing negative work for deceleration breaking along the long steep uphill tracks 5 to stop by the next station tracks 2; and

- Intermediate pathway tracks 4, which are connected between the bottom 24 of the long steep downhill tracks 3 and the bottom 25 of the long steep uphill tracks 5, and which are set on a horizontal level or along a curve slightly lower at its middle with a gradient of ±2-3 %o (not shown) to favour the subway drainage;

- Among all mention above, the horizontal plane through the lowest point of the intermediate pathway tracks 4 is taken as the reference plane 33, above which the height 34 on the top 9 of the long steep downhill tracks 3 and the height 35 on the top 10 of the long steep uphill tracks 5 are essentially the same. In this embodiment, preferably, the long steep downhill tracks 3 and the long steep uphill tracks 5 are symmetrically set up for the equal height, equal length and equal absolute of gradient (one negative and another positive). Of course, in other embodiments of this invention, for different needs upon the construction conditions and others, the long steep downhill tracks 3 and the long steep uphill tracks 5 can be not so symmetrical, so long as the kinetic energy of the gravity-train 1 has obtained from its gravitational potential energy upon its running through the long steep downhill tracks 3 can become zero, as being transformed back into the gravitational potential energy after it runs through the long steep uphill tracks 5. Theoretically according to the law of conservation of energy, gravitational potential energy and kinetic energy are interconvertible as mgh = ½mv², so long as the top 9 of the long steep downhill tracks 3 and the top 10 of the long steep uphill tracks 5 are essentially at the same height (34 and 35) above the reference plane 33. In this embodiment, both of the long steep downhill tracks 3 and the long steep uphill tracks 5 are longer and steeper than the ramps of the existing conventional train tracks. Specific numerical of the gradient and length of the gravity-train tracks, which as these parameters are related to the gravity-train acceleration, deceleration and achievable target speed, should be defined under comprehensive considerations of distance between stations, expected journey time or designed minimum time interval of journey, maximum passing capability and other factors. g In this embodiment, in order to ensure the gravity-train 1 to run smoothly, both of the long steep downhill tracks 3 and uphill tracks 5 are smoothly connected with the station tracks 2 and the intermediate pathway tracks 4, and the connecting parts of the tracks are set in a form of the appropriate vertical curves.

In this embodiment, part of the station tracks 2 near the outbound end comprises a forward and downward slope to connect with the top 9 of the long steep downhill tracks 3, making the gravity of the gravity-train 1 produce a gravitational component in the direction of train-running but slightly smaller than the absolute value of the running resistance, so as not causing the gravity-train 1 to slide unnecessarily when stopping at the station tracks 2 but benefiting the use of the running-resistance balancing engine with a smaller power to start the gravity-train 1 for its departure with assistance of this forward and downward slope. Or part of the station tracks 2 near the outbound end is configured and termed as the gravitational start tracks 11, on which the gravity-train 1 starts upon its gravity. In this embodiment, the gravitational start tracks 11 is used as an example to make explanations. In other embodiments of this invention, the station tracks 2 can also be set on a basically horizontal level. As shown in Figs 2a-2c, the rear end of the gravitational start tracks 11, i.e. the one away from the long steep downhill tracks 3, is connected through a rotatable structure of pestle socket joints 12 to the main part of the station tracks 2. The gravitational start tracks 11 through the flexible connection with a pestle 13 in one end and a socket 14 in another can slightly turn up and down around the rotatable structure of pestle socket joints 12 as a pivot, maintaining its continuity and smooth along the station tracks 2. The fore end 16 of the gravitational start tracks 11, i.e. the one toward the long steep downhill tracks 3, is set on a liftable facility, and the gravitational start tracks 11 can be situated on either of two operating positions: the first on a horizontal level, and the second with a forward and downward gradient making the gravity of the gravity-train 1 to generate a gravitational component in the direction of the gravity-train 1 to run, and this gravitational component is larger than the static friction between the gravity-train 1 and the gravity-train tracks as well as other running resistance. The fore end 16 of the gravitational start tracks 11 at the first operating position is placed above the top 9 of the long steep downhill tracks 3, while fore end 16 of the gravitational start tracks 11 at the second operating position forms a smooth connection 18 with the top 9 of the long steep downhill tracks 3.

In this embodiment, beneath the gravitational start tracks 11 there are supports based on a liftable supporting facility 17, which rising and falling makes the gravitational start tracks 11 turn up and down around the rotatable structure of pestle socket joints 12, switching between the first and second operating positions.

In this embodiment, beneath the gravitational start tracks 11 there are also some buffer facilities for shock absorption 19, enabling the gravitational start tracks 11 smoothly turn down from its first operating position to reach its second operating position without a big shock.

At its first operating position, the middle or 1/3 from the fore end 16 of the gravitational start tracks 11 is the front stopping point for the gravity-train 1. The gravitational start tracks 11 is supported without falling by the supporting facility 17, locked by a lock mechanism, when the gravitational start tracks 11 remains held at its first operating position. As soon as unlocking the lock mechanism, the gravitational start tracks 11 downturns a small angle at a slightly gentle angular- velocity for its fore end 16 to incline marginally downward to have a connection 18 with the top 9 of the long steep downhill tracks 3, wherein the supporting facility 17 is lowered directionally and thus also plays a guiding role in the accurate connection 18 between the downwardly inclined the fore end 16 of the gravitational start tracks 11 and the top 9 of the downhill tracks 3. In this embodiment, the gravity-train tracks can be set as underground lines, elevated lines, underground elevated lines, surface/underground lines, and surface/elevated lines.

In this embodiment, under the premise of using gravity as the main source of driving force for accelerating and braking the gravity-train 1 can retain some of structures and functions of a conventional train. As shown in Figs 3-5 of this embodiment, the gravity-train carriage 15 comprises a carriage body, an adjustable floor 28 flexibly connected to the carriage body, and a control device that can adjust the adjustable floor 28 to a desirable levelness during the gravity-train runs on the gravity-train tracks.

In other embodiments of this invention, a gravity-train carriage 15 can also have no adjustable floor 28 but use the safety seats with seat belts fixed to the carriage body, or have both of the adjustable floor 28 and safety seats.

In this embodiment, the length of the gravity-train carriage 15 with an adjustable floor 28 is similar to or slightly shorter than that of the short type of the train carriage among various conventional trains. The adjustable floor 28 is connected to the carriage body via a horizontal axis 22 in the middle of the adjustable floor 28, the axial direction of the horizontal axis 22 is parallel to the carriage chassis 21, perpendicular to the direction of the gravity-train 1 travelling, and the horizontal axis 22 is supported by the carriage chassis 21 and/or by two sidewalls of the carriage body. The front half and rear half of the adjustable floor 28 can act similarly like a teeter board around the horizontal axis 22 within a certain angle as needed for elevation-depression movement, which can be adjusted and controlled by the control device. In this embodiment, a plane through the horizontal axis 22 and parallel to the carriage chassis 21 refers as median plane. In Fig 4 and Fig 5, 28 (a) shows the adjustable floor set on median plane. The angle for the elevation-depression movement of the adjustable floor 28 means that between the front half of the adjustable floor 28 and the median plane. When the front half of the adjustable floor 28 is slightly elevated, the angle between the elevated front half of the adjustable floor 28 (b) and the median plane is termed as elevation angle 30 (Fig 4), and, when the front half of the adjustable floor 28 is slightly depressed, the angle between the depressed front half of the adjustable floor 28 (c) and the median plane is termed depression angle 31 (Fig 5). On the carriage chassis 21 and/or on the carriage sidewalls there set the adjustable supporting pillars (not shown in Figs 4 and 5) and snap-in facilities 32 to make the adjustable floor 28 positioned at several different elevation-depression angles. The mechanism of driving force for changing the elevation-depression angle can be hydraulic, pneumatic or other mechanical devices.

In this embodiment, the gravity-train carriage 15 also includes the sensors, such as those for position changes of fore and rear ends of the adjustable floor 28, to measure the levelness of the gravity-train carriage 15 and send the corresponding signals for the horizontal level to the control device on the gravity-train carriage 15.

As shown in Fig 6, in this embodiment, the gravity-train tracks also includes the signal devices of gradient change 29 near the positions where the gravity-train tracks gradient starts changing, to send the tracks gradient change signal to the control device on the gravity-train carriage 15 when the gravity-train 1 is to enter the section of the gravity-train tracks with the gradient change.

The control device can be located in the computer center of the gravity-train 1, to receive gradient change signals from the sensors on the carriage body and from the signal devices of gradient change 29 near the track gradient change points, and then to adjust and control the position changes in elevation-depression angle of the adjustable floor 28 (see Figs 3-6). For example:

When the gravity-train carriage 15 is located on the horizontal tracks, the adjustable floor 28 is positioned on the median plane parallel to the carriage chassis 21;

When the gravity-train carriage 15 is going to run from the horizontal tracks forward an downhill tracks, the sensors can immediately detect the forward depression trend of the carriage body, and the control device - computer collects the information on the gradient change from the sensors on the carriage body and from the signal devices of gradient change 29 near the track gradient change points and immediately sends orders to the adjustable supporting pillars 27 , snap-in facilities 32 and the mechanism of driving force for changing the elevation-depression angle. The adjustable floor 28 (b) is adjusted to a corresponding elevation angle 31 to continuously remain at its horizontal level or maintain a level within a small gradient (smaller than that of the track ramp) for the passengers still to feel their ride comfortable and smooth;

When the gravity-train carriage 15 is going to run from a horizontal tracks forward an uphill tracks, the sensors can immediately detect the forward elevation trend of the carriage body, and the control device - computer collects the information on the gradient change from the sensors on the carriage body and from the signal devices of gradient change 29 near the track gradient change points and immediately sends orders to the adjustable supporting pillars (not shown in the figures) , the snap-in facilities 32 and the mechanism of driving force for changing the elevation-depression angle. The adjustable floor 28 (c) is adjusted to a corresponding depression angle 31 to continuously remain at its horizontal level or maintain a level within a small gradient (smaller than that of the track ramp) for the passengers still to feel their ride comfortable and smooth;

When the gravity-train carriage 15 is going to run from a downhill tracks forward a horizontal tracks or from a uphill tracks forward a horizontal tracks, the sensors can immediately detect the forward elevation or depression trend of the carriage body, and the control device - computer collects the information on the gradient change from the sensors on the carriage body and from the signal devices of gradient change 29 near the track gradient change points and immediately sends orders to the adjustable supporting pillars (not shown in the figures) , the snap-in facilities 32 and the mechanism of driving force for changing the elevation-depression angle. The adjustable floor 28 is adjusted to its horizontal median level parallel to the carriage chassis 21, for the passengers to feel their ride comfortable and smooth; In this embodiment, the engine of the gravity-train 1 is the running-resistance balancing engine (not shown in the figures), different from and consuming a smaller power than that of a conventional train, playing no role as a driving force for train accelerating but for balancing the running-resistances (including the basic resistances and other additional resistances ) which is not related to the gradient of the gravity-train tracks during the gravity-train travelling on the whole gravity-train tracks, and assisting the train to start if necessary.

Thereafter, example analysis of the relevant data in this embodiment is given: 1) Aspect of the gravity-train tracks

As described in the technical solutions of this invention, the specifications for the parameters, length and gradient of the long steep downhill tracks 3 and the long steep uphill tracks 5 are related to the acceleration, deceleration and achievable target speed of train running, and should be defined under comprehensive considerations of distance between stations, proposed time or designed minimum time interval of journey, maximum passing capability of trains and other factors. Firstly on the distance between stations, there are two international trends of the average distance between subway stations: the shorter is averagely 1 km, while the longer 1.7 km. On the minimum time interval of journey, the latest design for Paris Metro is 85 s, while its maximum passing capacity of trains is 40 pairs (maximum number of trains passing through a line in one direction per hour). The data analysis in this invention takes as an example the underground tracks with the ground stations: the distance between stations of 1.2 km and the proposed time interval of journey <85 s, and carried out with Figs 1 and 2a- 2c as follows:

In Fig 1, the distance between two stations A and D is AD = 1.2 km, wherein AF = ED = 500 m, FE = BC = 200 m, AB is the length of the long steep downhill tracks 3, BC the intermediate pathway tracks 4 (on the reference plane 33), CD the long steep uphill tracks 5, AB = CD, FB = EC (corresponding to that the height 34 on top 9 of the long steep downhill tracks 3 is equivalent to the height 35 on top 10 of the long steep uphill tracks 5 above the reference plane 33), FB also the height between the start and end points of the long steep downhill tracks 3, AF the horizontal distance (500m) between the start and end points of the long steep downhill tracks 3. The data analysis in this embodiment sets the gradient of the long steep downhill tracks 3 as -105.10 %> (i.e. FB/AF = -105.10 %o, angle FAB « 6°), and so gets the length of the long steep downhill tracks 3 AB = 502.7 m, the height between its start and end points FB = 52.5 m, the corresponding acceleration a = 1.02 m/s² parallel to the long steep downhill tracks 3 along AB direction generated by the component 7 of gravity 6 (g = 9.8 m/s²), the time of 31.3 s used for completion of a uniformly accelerated motion through the long steep downhill tracks 3 (AB = 502.7m) at the given acceleration, the reached final speed of 32.1 m/s equivalent 115.5 km/h. The gradient of the long steep uphill tracks 5 is also 105.10 %o, and its length CD = 502.7 m, so that 68.8 s is the total time for running through AB (the long steep downhill tracks 3) + BC (the intermediate pathway tracks 4) + CD (the long steep uphill tracks 5).

Specific discussions:

(1) To analyse the gradient aspect: A main line of the conventional subway has a maximum gradient of 30 %o, and 35 %o can be used for the difficult section; Tehran Metro Line has used a maximum gradient of 50 %o, with a good operation; the linear motor train line design generally has a maximum gradient of 50 %o, or 55 %o for difficult sections, and practical application up to 80 %o. Comparing the international trend of line-steeping, 105.10 %o is feasible for the gradient of the gravity-train tracks in the above example design since the adjustable floor 28 in the gravity-train carriages 15 can be angularly adjusted for the leveling within a marginal degree (See Fig 3 and more details below) for the passengers to feel a good ride.

(2) To analyse the speed aspect: A maximum speed lOOkm/h is used at Beijing Subway Airport Line, Shanghai Metro Line No.11 as well as its extensions, and Shenzhen Metro Longgang Line among others; 120km/h is used at Guangzhou Metro Line 3 and its North Extension; while a maximum speed 128 km/h is used at San Francisco Subway. To achieve a maximum passing capability must be guaranteed with a relatively high running speed, so that a maximum speed of 115 km/h is somehow appropriate as described above in the design for the gravity-train 1.

(3) To analyse the time interval of journey: It is 68.8 s <85 s as described above in the design of the gravity-train 1, favouring a maximum passing capacity of trains of not less than 30 pairs and an expectation for 40 pairs.

(4) To analyse the track depth aspect: The maximum depth is 59 m in a London Underground station, 63 m in a Paris Metro station, 90 m in Moscow Metro, 100 m in Dalian Metro, and 120 m in Pyongyang Metro. Due to the rising prices of urban lands and full utilization of shallow underground, the deep subway has got attention. 52.2 m is within an acceptable range as a maximum depth described above in the design of the gravity-train tracks.

As for station tracks 2, its outbound section has a tiny forward and downward slope, not enough to cause the stationed gravity-train 1 to slide unnecessarily, which can be set as -3 %o in this embodiment. After unlocking of lock mechanism, the gravitational start tracks 11 downturns a small angle around the rotatable structure of the pestle socket joints 12 as a pivot, for its fore end 16 to incline marginally downward to have a connection 18 with the top 9 of the long steep downhill tracks 3. The forward and downward gradient of the gravitational start tracks 11 at its second operating position can be set to -6 %o in this embodiment. The intermediate pathway tracks 4 are set on a horizontal level or along a curve slightly lower at its middle (to favour drainage) with its gradient set as -2 %o ~ meddle lower ~ 2 %o in this embodiment. As the theory and practice indicate that a trains gravitational component along a downhill ramp of -4—5 %o is in equilibrium with the trains running-resistance, the designed gradients of the outbound section of the station tracks 2, of the gravitational start tracks 11 (at the second operating position) and of the intermediate pathway tracks 4 are reasonable.

2) Aspect of the gravit -train 1

As shown in Figs 3-5, the function of the adjustable floor 28 in the gravity-train carriage 15 is that when the gravity-train carriage 15 runs along the long steep downhill tracks 3 and the long steep uphill tracks 5 with a relatively large gradient the adjustable floor 28 is able to be adjusted to a appropriate elevation-depression angle to remain essentially at its horizontal level or maintain a level within a small gradient for the passengers still to feel their ride comfortable and smooth, and such small gradient is therefore termed as "comfortable-ride small gradient". Fig 3 shows the schematic side view of the adjustment of the activities of the adjustable floor front half 23 when the gravity-train carriage 15 runs along the long steep downhill tracks 3 with a gradient of -105.10 %o in this embodiment. The length of the adjustable floor 28 is related to that of the gravity-train carriages 15. Currently in the world, there are three types of subway train carriages: A type is 22 m long, B type 19 m, and C type long 15-19 m. As described in technical solutions of this invention, the length of the gravity-train carriage 15 is similar to or slightly shorter than that of the short type among various conventional trains, thus in this embodiment the length of the gravity-train carriage 15 is set to about 15 m, wherein the adjustable floor 28 is 14 m long. In Fig 3, ML stands for horizontal line 20, LG for the long steep downhill tracks 3, ST for the carriage chassis 21, O for the horizontal axis 22 of the adjustable floor 28, OJ for the front half 23 (a) of the adjustable floor located on the median plane in parallel with carriage chassis 21 and set to 7 m long (0.5 X 14m = 7m), OK for the front half 23 (b) of the adjustable floor adjusted to the horizontal level, OH for the front half 23 (c) of the adjustable floor adjusted to a level with the "comfortable-ride small gradient" to maintain a comfortable ride. As described above when the adjustable floor 28 is adjusted to a level with certain slope as "comfortable- ride small gradient" passengers still feel their ride comfortable and smooth. In fact, the existing train carriages with the fixed floor do not always run along the horizontal tracks, sometimes on a ramp within a specification of such as a gradient 30 %o, the same for the carriage floor which located in the gradient 30 %o does not affect the ride but still offer a comfortable feeling. The gradient 30 %o can be therefore considered as a "comfortable-ride small gradient". With the steeping trend of the train lines, it has been found that, when a train runs on the tracks with a gradient of 50 %o, the ride feeling remains unaffected but still comfortable. For instance, Tehran Metro Line No. 1 has used a maximum gradient of 50 %o, and operated well for several years, without abnormality in this aspect, indicating that a maximum gradient of 50 %o is feasible choice for a small slope to maintain a comfortable ride, gradient 50 %o can be therefore considered as the "comfortable-ride small gradient". The traction of existing train-engines has gradually been increased with the steeping of railways, wherein the train with a rotating motor runs on the lines with a gradient of ^30 %o, while the train with a larger power engine e.g. linear motor can run on the lines with a gradient of 80 %o. The lines design for the linear motor train generally has a maximum gradient of 50 %o, or 55 %o for difficult sections, and practical application up to 80 %o, while 100 %o is the theoretical maximum gradient of a ramp for the train with the linear motor to run on. This is another indication that a plane with a gradient of 50 %o or even 80 %o can also be taken as the plane with the "comfortable-ride small gradient". In this invention designing an adjustable floor 28 in the gravity-train carriage 15 is to maintain a comfort ride for passengers, so when the gravity-train carriage 15 is running on the gravity-train tracks, following their gradient changes, the adjustable floor 28 can be adjusted and controlled on the horizontal level (OK), or to a small gradient level (OH) with said "comfortable-ride small gradient" such to maintain the comfort ride. In this embodiment, LG shows the long steep downhill tracks 3 with a gradient of -105.10 %o, on which if the front half 23 (a) of the adjustable floor from the median plane (OJ) paralleling the carriage chassis 21 adjusted to a horizontal level (OK), about 70 cm is the outstretched length JK of the adjustable supporting pillar 26 beneath the front end of the adjustable floor 23 (b); while if the front half 23 (a) of the adjustable floor from the median plane (OJ) paralleling the carriage chassis 21 adjusted to a small gradient slope (OH) with the "comfortable-ride small gradient" of -50 o to maintain a comfortable ride, about 37 cm is the outstretched length JH of the adjustable supporting pillar 27 beneath the front end of the adjustable floor 23 (c); and if adjusted to another small gradient slope (also expressed by OH) with the "comfortable-ride small gradient" of -80 %o to maintain a comfortable ride, only about 17 cm is the outstretched length (also expressed by JH) of the adjustable supporting pillar 27 beneath the front end of the adjustable floor 23 (c). The rotatable horizontal axis 22 as a pivot O of the adjustable floor 28 is in the middle of the adjustable floor 28, essentially balanced between its two half (front and rear sides) divided by the axis 22 as a pivot O as a teeter board which does not need a large driving force to adjust its elevation-depression angle. As the above analysis and calculation regarding the adjustable floor 28, the driving force needed to adjust the elevation-depression angle is not so large and the adjustment range required is relatively small, such a sensitive and accurate regulation of the adjustable floor 28 via the control device on the gravity-train carriages 15 can be achieved. The adjustment situations of the adjustable floor 28 when the gravity- train carriage 15 runs along the long steep uphill tracks 5 (not shown in Fig 3 but may refer to Fig 5) and of the rear half of adjustable floor 28 (not shown in Fig 3 but may refer to Figs 4 and 5) may be deduced in the same way with no repetition.

For the gravity-train 1, the engine is no longer a main source of driving for its accelerating. The gravity-train 1 uses the running-resistance balancing engine for balancing the running resistance (including the basic and other additional resistances) which not related to the gradient of the gravity- train tracks during the travelling of the gravity-train 1. The train running resistance is usually about 5 %o of the train weight, much smaller than the driving force for the train accelerating (usually about 100 %o of the train weight). Therefore, the power consumed by the running-resistance balancing engine used in the gravity-train 1 is not large, the costs, the load of the related facilities of the entire power supply system and so on will be reduced.

The above data analysis shows that a gravity-train system with distance between stations of 1.2 km and time interval of journey <85 s is feasible. Further analysis indicates that, under the same parameters of distance between stations, time interval of journey and others there are many different parameters available; under the different premise of distance between stations, time interval of journey and others, various parameters of the gravity-train 1 and the gravity-train tracks can also preferably used for the gravity-train system.

In summary, the technical solutions in this embodiment are realistic, and a lot of energy consumptions can be saved. Embodiment 2

This embodiment describes a method of operating the gravity-train system, in which the gravity is used as its main source of driving force for the gravity-train accelerating and braking (see Figs 1-6), comprising the following steps:

The gravity-train 1 starts on the gravitational start tracks 11 or on the forward and downward slope at the fore part of the station tracks 2 simultaneously the running-resistance balancing engine ignites, the gravity-train 1 exits the outbound end of the present station tracks 2 and reaches the long steep downhill tracks 3;

On the long steep downhill tracks 3, the adjustable floor 28 is located in the desired level degree adjusted by the control device; under the action of the gradient of the long steep downhill tracks 3, the gravity 6 of the gravity-train 1 generates a gravitational component 7 for the gravity-train 1 accelerating along the direction of its travelling with assistance of the running-resistance balancing engine power, making the gravity-train running acceleratedly to the intermediate pathway tracks 4 to achieve the target speed; On the intermediate pathway tracks 4, the adjustable floor 28 is parallel to the carriage chassis 21 adjusted by the control device ; with the running-resistance balancing engine power the gravity-train 1 runs uniformly at the target speed until it reaches the long steep uphill tracks 5;

The gravity-train 1 runs onto the long steep uphill tracks 5 with an initial velocity of the target speed and with the assistance of the running-resistance balancing engine power; the adjustable floor 28 is located in the desired level degree adjusted by the control device; under the action of the gradient of the long steep uphill tracks 5, the gravity 6 of the gravity-train 1 generates a gravitational component 8 for the gravity-train 1 decelerating along the direction of its travelling, making the gravity-train 1 running deceleratedly until it reaches the inbound end of the next station tracks 2 and the train speed approaches zero ;

On the next station tracks 2, the adjustable floor 28 is parallel to the carriage chassis 21 adjusted by the control device; the gravity-train 1 stops simultaneously the running-resistance balancing engine turns off.

Thereafter, the method of operating the gravity-train system described in embodiment 1 as an example to illustrate this invention in details:

SI : The gravity-train 1 stops on the part of station tracks 2 near their outbound end with the forward and slightly downward slope but not causing the gravity-train 1 to slide down, the control device - computer automatic control system on the train makes the information analysis and data processing on the gravity-train tracks conditions ahead, the running-resistance balancing engine ignites and simultaneously the train stop mechanism is removed, and so the gravity-train 1 starts. Alternatively, the gravity-train 1 stops in the middle or 1/3 from the fore end 16 of the gravitational start tracks 11 of the station tracks 2, the control device - computer automatic control system on the train makes the information analysis and data processing on the gravity-train tracks conditions ahead, the running- resistance balancing engine ignites and simultaneously the train stop mechanism is removed, while the locking mechanism is unlocked and the gravitational start tracks 11 immediately vertically downturns a small angle at a gentle angular velocity from its first operating position to the second operating position for their fore end 16 to incline marginally downward to have a connection 18 with the top 9 of the long steep downhill tracks 3, and so the gravity-train 1 starts as under the action of a gravitational component in the forward and downward direction. S2: While the gravity-train 1 runs forward the long steep downhill tracks 3, the control device - computer automatic control system on the train timely issues a directive to adjust and control the adjustable floor 28 (b) positioned at a corresponding elevation angle 30, so that, while the gravity-train 1 runs down along the long steep downhill tracks 3, the adjustable floor 28 (b) continuously remains at its horizontal level or maintains at a level within a "comfortable-ride small gradient" (smaller than that of the track ramp) for the passengers still to feel their ride comfortable and smooth.

S3: The gravity-train 1 acceleratedly runs down under the action of the gravitational component 7 of the trains gravity 6 in parallel to the long steep downhill tracks 3. Due to the gradient of the long steep downhill tracks 3 is relatively large , the gravitational component 7 of the gravity 6 is relatively strong and does more work which also as the long steep downhill tracks 3 is relatively long. Such a long steep downhill tracks 3 with a large height variation from their top 9 to their bottom 24 can provide a high gravitational potential energy to be transformed into kinetic energy, and so becomes a main resource of driving force for the gravity-train 1 to accelerate while the running-resistance balancing engine uses a small power for balancing the running resistance. While the gravitational potential energy is rapidly transformed into kinetic energy, the gravity-train 1 obtains the acceleration needed to run to achieve the target speed at the bottom 24 of the long steep downhill tracks 3. Meanwhile, the control device - computer automatic control system on the train makes the information analysis and data processing on the gravity-train tracks conditions ahead.

S4: While the gravity-train 1 runs forward the intermediate pathway tracks 4, the control device - computer automatic control system on the train timely issues a directive to adjust and control the adjustable floor 28 (a) positioned on the median plane parallel to the carriage chassis 21, so that, while the gravity-train 1 runs along the intermediate pathway tracks 4, the adjustable floor 28 continuously remains at a basically horizontal plane parallel to the intermediate pathway tracks 4 for the passengers to feel their ride comfortable and smooth.

S5: On the intermediate pathway tracks 4, since the running-resistance balancing engine uses a small power for balancing the running resistance, the gravity-train 1 runs uniformly at the above -mentioned target speed on the intermediate pathway tracks 4, approaching the bottom 25 of the long steep uphill tracks 5 while the control device - computer automatic control system on the train makes the information analysis and data processing on the gravity-train tracks conditions ahead.

S6: While the gravity-train 1 runs rushes up the long steep uphill tracks 5, the control device - computer automatic control system on the train timely issues a directive to adjust and control the adjustable floor 28 (c) positioned at a corresponding depression angle 31, so that, while the gravity- train 1 runs up along the long steep uphill tracks 5, the adjustable floor 28 (c) continuously remains at its horizontal level or maintains at a level within a "comfortable-ride small gradient" (smaller than that of the track ramp) for the passengers still to feel their ride comfortable and smooth. S7: The gravity-train 1 deceleratedly runs up under the action of the gravitational component 8 of the trains gravity 6 in parallel to the long steep uphill tracks 5. According to the law of conservation of energy, gravitational potential energy and kinetic energy are interconvertible as mgh = ½mv², while in this embodiment, the long steep downhill tracks 3 and the long steep uphill tracks 5 are symmetry, for the equal height, equal length and equal absolute value of gradient (one negative and another positive), or the top 9 of the long steep downhill tracks 3 and the top 10 of the long steep uphill tracks 5 are essentially at the same height (34 and 35) above the reference plane 33 through the lowest point of the intermediate pathway tracks 4, so under the circumstance excluding the interference from other resistance (the train running resistance is balanced by the running-resistance balancing engine power), if the gravity-train 1 acceleratedly runs down from the top 9 of the long steep downhill tracks 3 to reach the bottom 24 of the long steep downhill tracks 3 (equivalent to the reference plane 33), the gravitational potential energy of the gravity-train 1 on the top 9 relative to the bottom 24 is completely transformed into the trains kinetic energy, with which the gravity-train 1 deceleratedly rushes up from the bottom 25 of the long steep uphill tracks 5 (equivalent from the reference plane 33) to the top 10 of the long steep uphill tracks 5, all of the kinetic energy of the gravity-train 1 at the bottom 25 is just transformed into the gravitational potential energy of the train on the top 10 relative to its bottom 25, so that the gravity of the gravity-train 1 becomes the main source of driving force for decelerating and braking during the gravity-train 1 runs up along the long steep uphill tracks 5 ; during the kinetic energy is transformed into the gravitational potential energy, the gravity-train 1 obtains a negative acceleration needed for its braking, and its speed is reduced to be extremely low as approaching the top 10 of the long steep uphill tracks 5. Meanwhile, the control device - computer automatic control system on the train makes the information analysis and data processing on the gravity-train tracks conditions ahead.

S8: While the gravity-train 1 slowly runs into the station tracks 2 of the next station, the control device - computer automatic control system on the train timely issues a directive to adjust and control the adjustable floor 28 (a) positioned on the median plane parallel to the carriage chassis 21, so that, while the gravity-train 1 flatly decelerate along the station tracks 2 to stop, the adjustable floor 28 continuously remains at its basic level for the passengers to feel their ride comfortable and smooth, the running-resistance balancing engine is off, the gravity-train 1 stops on the part of the station tracks 2 near their outbound end with a forward and slightly downward slope but not causing the gravity-train 1 to slide down, or it stops on the gravitational start tracks 11 of the station tracks 2 with the gravity- trains 1 front located in the middle or 1/3 from the fore end 16 of the gravitational start tracks 11 of the station tracks 2, ready for the next start to travel.

As shown above in this embodiment, the method of operating the gravity-train system in which the trains gravity is used as a main source of driving force for the gravity-train accelerating and decelerating to brake can greatly reduce the energy consumption, in comparison with the prior art. The above mentioned embodiments are presented by way of illustration only but not limitation. It will be appreciated by those skilled in the relevant arts that various changes and modifications may be made thereto without departing from the spirit and scope of the invention. Therefore these equivalent technical solutions also fall within the scope of the invention which should be defined in accordance with the appended claims.

Claims

WO 2014/133432 PCT/SE2014/000002 Claims

1. A gravity-train system using the train gravity as its main source of driving force for train accelerating and braking, characterized in that, the system comprises gravity-train 1 and gravity-train tracks. The gravity-train 1 includes:

Gravity-train carriages 15, a gravity-train 1 has one or several gravity-train carriages 15 which can run on the tracks with steep slope on a long ramp; and

Running-resistance balancing engine, to produce power for the gravity-train 1 to balance the running resistance excluding the resistance related to the gradient of the gravity-train tracks. The gravity-train tracks include:

Station tracks 2, including both ends at the outbound and inbound, used for the gravity-trains 1 to start and stop;

Long steep downhill tracks 3, the top 9 of the long steep downhill tracks 3 is connected to the outbound end of the present station tracks 2, the length and gradient of the long steep downhill tracks 3 are suitable for the gravity-train 1 upon its gravity doing positive work for acceleration running along the long steep downhill tracks 3 to reach the target speed;

Long steep uphill tracks 5, the top 10 of the long steep uphill tracks 5 is connected to the inbound end of the next station tracks 2, the length and gradient of the long steep uphill tracks 5 are suitable for the gravity-train 1 upon its gravity doing negative work for deceleration breaking along the long steep uphill tracks 5 to stop on the next station tracks 2;

Intermediate pathway tracks 4, which are connected between the bottom 24 of the long steep downhill tracks 3 and the bottom 25 of the long steep uphill tracks 5, and the intermediate pathway tracks 4 are set on a horizontal level or along a curve slightly lower at its middle with a gradient of - 2- - 3 %o ~ 2-3 o to favour the subway drainage; Wherein the horizontal plane through the lowest point of the intermediate pathway tracks 4 is taken as the reference plane 33, above which the height 34 on the top 9 of the long steep downhill tracks 3 and the height 35 on the top 10 of the long steep uphill tracks 5 are essentially the same.

2. A gravity-train system according to claim 1, characterized in that, both of the long steep downhill tracks 3 and the long steep uphill tracks 5 are smoothly connected to the station tracks 2 and the intermediate pathway tracks 4.

3. A gravity-train system according to claim 1, characterized in that, part of the station tracks 2 near their outbound end comprises a forward and downward slope, which can make the gravity of the gravity-train 1 produce a gravitational component in the direction of train-running but slightly smaller than the absolute value of the running resistance, on this forward and downward slope the gravity-train 1 can start by the running-resistance balancing engine's power with the assistance of the gravitational component; or the part of the station tracks 2 near their outbound end is configured as the gravitational start tracks 11, on which the gravity-train 1 starts upon its gravity.

4. A gravity-train system according to claim 3, characterized in that, the rear end of the gravitational start tracks 11, i.e. the one away from the long steep downhill tracks 3, is connected through a rotatable structure of pestle socket joints 12 to the main part of the station tracks 2, while the fore end 16 of the gravitational start tracks 11, i.e. the one toward the long steep downhill tracks 3, is set on a liftable facility ; which allows the gravitational start tracks 11 to lay on either of two operating positions: the first on a horizontal level, and the second with a forward and downward gradient; at the first operating position the fore end 16 of the gravitational start tracks 11 is located above the top 9 of the long steep downhill tracks 3, while at the second operating position the fore end 16 of the gravitational start tracks 11 is smoothly connected to the top 9 of the long steep downhill tracks 3 and in this case the gravity of the gravity-train 1 on the gravitational start tracks 11 produce a larger gravitational component which is in the direction of the gravity-train 1 running, is greater than the absolute value of the running resistance and the static friction between the gravity-train 1 and the gravity-train tracks, and makes the gravity-train 1 to start upon its gravity.

5. A gravity-train system according to claim 4, characterized in that, beneath the gravitational start tracks 11 there are supports with a liftable supporting facility 17, which through rising and falling makes the gravitational start tracks 11 turn up and down around the rotatable structure of the pestle socket joints 12 to switch the gravitational start tracks 11 between the first operating position and the second operating position.

6. A gravity-train system according to claim 4, characterized in that, beneath the gravitational start tracks 11 there are also some buffer facilities for shock absorption 19.

7. A gravity-train system according to claim 1, characterized in that, the gravity-train tracks can be set as underground lines, elevated lines, underground/elevated lines, surface/underground lines, and surface/elevated lines.

8. A gravity-train system according to claim 1, characterized in that, the gravity-train carriage 15 includes a carriage body, includes an adjustable floor 28 flexibly connected to the carriage body, and / or safety seats with seat belts fixed on the carriage body, and includes a control device that can adjust the adjustable floor 28 to a desired level degree set according to the circumstances information regarding the levelness of the carriage body and the gradient of the gravity-train tracks on which the gravity-train 1 runs.

9. A gravity-train system according to claim 8, characterized in that, the adjustable floor 28 is connected to the carriage body via a horizontal axis 22 in the middle of the adjustable floor 28, the axial of the horizontal axis 22 is parallel to the carriage chassis 21 and perpendicular to the direction of the gravity-train 1 travelling, around the horizontal axis 22 the adjustable floor 28 can turn up and down accordingly.

10. A gravity-train system according to claim 8, characterized in that, the gravity-train carriage 1 also includes some sensors to measure the levelness of the gravity-train carriage 15 and send the corresponding signals for the horizontal level to the control device on the gravity-train carriage 15.

11. A gravity-train system according to claim 8, characterized in that, on the inner walls of the carriage body there is a set of snap-in facilities 32, which fixes the position limit of the adjustable floor 28 at such a desired level degree after the control device adjustment of the adjustable floor 28 upon the gravity-train 1 running along the gravity-train tracks e.g. the long steep downhill tracks 3 or the long steep uphill tracks 5 etc..

12. A gravity-train system according to claim 1 or 8, characterized in that, the gravity-train tracks also includes the signal devices of gradient change 29 near the positions where the gradient of the gravity- train tracks starts changing, to send the gradient change signal to the control device on the gravity- train carriage 15 when the gravity-train 1 is to enter the section of the gravity-train tracks with the gradient change.

13. A method of operating the gravity-train system according to any of claims 1-12, characterized in that, the method comprises the following steps:

The gravity-train 1 starts on the gravitational start tracks 11 or on the forward and downward slope at the fore part of the station tracks 2 and simultaneously the running-resistance balancing engine ignites, the gravity-train 1 exits the outbound end of the present station tracks 2 and reaches the long steep downhill tracks 3;

On the long steep downhill tracks 3, the adjustable floor 28 is located in the desired level degree adjusted by the control device ; under the action of the gradient of the long steep downhill tracks 3, the gravity 6 of the gravity-train 1 generates a gravitational component 7 for the gravity-train 1 accelerating along the direction of the gravity-train 1 travelling with assistance of the running- resistance balancing engine's power, making the gravity-train running acceleratedly to the intermediate pathway tracks 4 to achieve the target speed;

On the intermediate pathway tracks 4, the adjustable floor 28 is parallel to the carriage chassis 21 adjusted by the control device; with the running-resistance balancing engine's power the gravity-train 1 runs uniformly at the target speed until it reaches the long steep uphill tracks 5;

The gravity-train 1 runs onto the long steep uphill tracks 5 with an initial velocity of the target speed and with the assistance of the running-resistance balancing engine power; the adjustable floor 28 is located in the desired level degree adjusted by the control device; under the action of the gradient of the long steep uphill tracks 5, the gravity 6 of the gravity-train 1 generates a gravitational component 8 for the gravity-train 1 decelerating along the direction of train-travelling, making the gravity-train 1 running deceleratedly until it reaches the inbound end of the next station tracks 2 and the train speed approaches zero ;

On the next station tracks 2, the adjustable floor 28 is parallel to the carriage chassis 21 adjusted by the control device ; the gravity-train 1 stops simultaneously the running-resistance balancing engine turns off.