CA1082521A - Method and apparatus for obtaining a controlled degree of ballast compaction in the tamping and leveling of a track - Google Patents
Method and apparatus for obtaining a controlled degree of ballast compaction in the tamping and leveling of a trackInfo
- Publication number
- CA1082521A CA1082521A CA250,281A CA250281A CA1082521A CA 1082521 A CA1082521 A CA 1082521A CA 250281 A CA250281 A CA 250281A CA 1082521 A CA1082521 A CA 1082521A
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- Canada
- Prior art keywords
- track
- tamping
- ballast
- jacking
- control
- Prior art date
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Abstract
Abstract of the Disclosure A controlled degree of ballast compaction is obtained with a mobile track tamping and leveling machine which com-prises a track holding device holding the track at a leveled position under the control of an error signal from a refer-ence system. The track is raised and ballast is compacted under the points of intersection between the track rails and ties, the ballast being pressed against the held track until it has reached a controlled degree of compaction.
Jacking of the track is terminated before tamping.
Jacking of the track is terminated before tamping.
Description
;~` ~
10825Zl The present invention relates to improvements in track surfacing operations, and more particularly in the tamping and leveling of a track consisting of rails mounted on ties having two elongated edges extending transversely of the rails and two ends extending in the direction of the rails, the rails and ties intersecting at points spaced in the direction of elongation of the track and the ties rest-ing on ballast. The elongated edges of adjacent ones of the ties define cribs therebetween, and the track is leveled or graded in relation to a reference system.
In known t~ack leveling methods, the ballast is compact-ed under the ties, and more particularly under the points of intersection, by vibratory pressure exerted upon the ballast under the ties inwardly from the two longitudinal tie edges whereby the progressively more compacted ballast raises the track, the track being independently lifted be-fore and/or during the ballast tamping, if desired, until it has reached the leveled position determined by a refer-ence system including a pickup and transmitter of an error signal for leveling the track in response to the error sig-nal. While such track surfacing has been found quite use-ful, the desired degree of ballast compaction under the ties has not always been achieved.
It has also been proposed to provide mobile track tamping machines with a tamping tool assembly vertically movably mounted on a machine frame for tamping a respective one of the ties, such an assembly comprising a pair of opposed vibratory tamping tools arranged for immersion in the cribs adjacent the tie and for reciprocation in the direction of track elongation,with the tie positioned be-
10825Zl The present invention relates to improvements in track surfacing operations, and more particularly in the tamping and leveling of a track consisting of rails mounted on ties having two elongated edges extending transversely of the rails and two ends extending in the direction of the rails, the rails and ties intersecting at points spaced in the direction of elongation of the track and the ties rest-ing on ballast. The elongated edges of adjacent ones of the ties define cribs therebetween, and the track is leveled or graded in relation to a reference system.
In known t~ack leveling methods, the ballast is compact-ed under the ties, and more particularly under the points of intersection, by vibratory pressure exerted upon the ballast under the ties inwardly from the two longitudinal tie edges whereby the progressively more compacted ballast raises the track, the track being independently lifted be-fore and/or during the ballast tamping, if desired, until it has reached the leveled position determined by a refer-ence system including a pickup and transmitter of an error signal for leveling the track in response to the error sig-nal. While such track surfacing has been found quite use-ful, the desired degree of ballast compaction under the ties has not always been achieved.
It has also been proposed to provide mobile track tamping machines with a tamping tool assembly vertically movably mounted on a machine frame for tamping a respective one of the ties, such an assembly comprising a pair of opposed vibratory tamping tools arranged for immersion in the cribs adjacent the tie and for reciprocation in the direction of track elongation,with the tie positioned be-
-2- ~
~0825Zl tween the opposed tools, and an additional vibratory tamp-ing tool arranged for immersion in the ballast adjacent the end of the tie and for reciprocation in a direction trans-verse to the direction of track elongation. With such an arrangement, the ballast is "boxed in" between the tamping tools substantially from the point of intersection of the rail and tie to the end of the tie, thus preventing the outward displacement of ballast during the tamping operation.
However, no control over the leveling of the track or the degree of ballast compaction is possible with such known track tampers because they neither comprise a leveling re-ference nor a tamping control.
It is also known to level track solely by tamping the ballast under the ties. In such track leveling machines, only opposed tamping tools reciprocated in the direction of track elongation are used and a control terminates the tamping operation in response to a reference signal indi-cating the desired track level. If the track must be raised to the desired level through a considerable lifting stroke, 2Q such machines also use independent track lifting mechanisms.
However, controlled uniform ballast compaction cannot be achieved with such machines since the ballast may escape laterally when the tamping pressure in the direction of track elongation exceeds a given degree while, in other track sections, the desired track level has been reached before the ballast has been sufficiently compacted.
Furthermore, it has been proposed to assure the main-tenance of a desired track level even under high tamping pressures by holding the track in position d~ring tamping, the track holding being so controlled that the track will .. ... . . .
' ' . . '. ~ ., ' ~' '; . . . ~
.
108ZSZl not be raised beyond the desired level during tamping. This prevents uncontrolled raising of the track but it does not assure the termination of the tamping when a desired degree of ballast compaction has been reached.
Thus, conventional track surfacing methods and apparatus have not been able to assure a desired, preferably uniform and optimal maximum, degree of ballast compaction under each tie over a long track section. It is, therefore, ~he pri-mary object of this invention to obtain such ballast com-paction, which is particularlyimportant in track sections designed for high-speed trains.
This and other objects are accomplished by the inven-tion in a method of leveling a track in relation to a refer-ence system by holding the track in the leveled position under the control of the reference system in the region of tamping, the ballast being pressed against the held track until it has reached a controlled degree of compaction.
The track is jacked up towards the leveled position and track jacking is terminated tenths of seconds up to several seconds before track tamping has been completed, the bal-last being compacted under the points of intersection of the ties and rails by vibratory pressure exerted upon the ballast under the ties inwardly from the two longitudinal tie edges and preferably from the tie ends. This produces not only a high degree of accuracy in the track level but also on optimally and uniformly compacted ballast bed.
Since tamping proceeds always simultaneously with jacking, track surfacing according to the present invention does not disturb the position of those ballast pieces whose sharp edges or corners bite into the underside of wooden . . .
ties when the track settles on the ballast bed, thus leav-ing the ballast enmeshed with the ties. This is of parti-cular advantage in high-speed traffic sections where the passing trains have strongly settled the track, the method of this invention providing for the track to be lifted during leveling with the conventional track lifting mechanism with-out destroying the intermeshing relationship of the ties and ballast. Tamping while jacking according to the inven-tion, the ballast piec~s remain undistur~ed in~heir re-lationship to the undersides of the ties and are even press-ed further into the undersides when the tamped ballast presses upwardly against the held track after jacking has ceased. This also assures a particularly sensitive approach of the track to the leveled position since the track is not torn out of its settled~osition but progressively p~essed from the settled into the leveled position, which impr3ves the accuracy of the leveling operation.
A mobile track tamping and leveling machine according to the present invention combines a known type of a level-ing reference system and of a tamping tool assembly which comprises not only a pair of opposed vibratory tamping tools -~ but preferably also an additional vibratory tamping tool adjacent the tie end with a track holding device holding the track at the leveled position controlled by the error signal from the reference system. Furthermore, a control regulates the track jacking and the drive means for the re-ciprocation and for the vibration of the tamping tools so that jacking and tamping initially proceed simultaneously but jacking is terminated before ~mping has been completed.
With this combination of structures mounted on the ~... . . . . . .
. , ., , ' ~ -.. ~ . . .
108ZS;21 mobile machine frame, the track will be leveled automatically and the ballast tamping will be terminated automatically when the optimal ballast compaction has been reached, the machine being readily adaptable by the control to differing ballast conditions while assuring long-lasting ballast com-paction.
The above and other objects, advantages and features of the present invention will become more apparent from the following detailed description of a now preferred em-bodiment thereof, taken in conjunction with the single figure of accompanying drawing.
The drawing schematically shows an embodiment of a ballast tamping and track leveling machine with a control circuit 41 for the operation of crib and end tamping tools 8, 9,track lifting and leveling unit 12 and a track holding mechanism 51. As shown in the drawing, the error signal from reference signal pickup and transmitter 6 is transmitted to sum-and-difference amplifier 43 which comprises an adjustable resistance set to indicate the desired value, the error signal being compared with the set value in the amplifier. The com-parison signal is transmitted from amplifier 43 to stepping switch 44 whose switching steps are adjustable. Depending on the adjusbm~ of the switch, contact 45 is actuated in response to the comparison signal received, which contact places the drives for reciprocation of the tamping tools and for track lifting and leveling unit 12 into a state of readiness. When switch 44 moves contact 45 into its lower position, as shown in FIG. 5, which produces a state of readiness for track lifting, switch 42 is operated to transmit the comparison or error signal directly to solenoid valve 47, which preferably is ... . ..
.; .
10825Zl a servo valve. This valve is arranged in the hydraulic supply conduit leading from tank 23 to lifting cylinder 22 and opening thereof permits hydraulic fluid flow to the cy-linder for lifting unit 12 to raise the track in response to the error signal. However, track lifting as well as reciprocation of the tamping tools is effected only when limit switch 48 affixed to the machine frame in the path of the vertical movement of tamping tool assembly 7 is tripped upon lowering of the tamping tools assembly, the limit switch being connected to relay 49 which actuates control switch 46 in the electrical connection between switch 42 and servo valve 47. The relay also actuates control switches 57 for operation of the tamping tools so that, depending on the position of contact 45 controlled by switch 44, servo valve 47 controlling the track lifting or servo valve 50 controlling the tamping tool reciprocation is actuated.
The machine operation is controlled in the following manner:
When the comparison or error signal detected and trans-mitted by amplifier 43 is below the tolerance, i.e. the switching step, set at switch 44, contact 45 connected to switch 44 is in the illustrated upper position, placing the hydraulic supply to the tamping tool drives into a state of readiness. When the error signal surpasses the set tolerancej switch 44 moves contact 45 from its upper end position to its lower end position to close switch 42 and place the hydraulic supply to lifting unit 12 into a state of readiness. Assuming control switches 46 and 57 to be closed upon tripping of limit switch 48 caused by lowering of the tamping tool assembly, servo valve 47 will be opened a ,, , .. . . .
and the track will be raised by unit 12 as long as the error signal value exceeds that of the set switching step and until it is equal thereto, after which, i.e. in the period between the set switching step value and the value of the desired level, servo valve 47 is closed and servo valve 50 remains open for further compaction of the ballast by the squeezing tamping tools after track jacking has been terminated. Closing of valve 47 causes unit 12 to dis-continue lifting the track, the illustrated dump position of valve 47 permitting fluid to flow back from cylinder 22 into tank 23 to allow the track to be further raised by tamping.
Track holding mechanism 51 is mounted in the range of the tamping tool assembly 90 as to prevent the tamped ballast from raising the track above the desired level determined by the reference system 5. In the illustrated embodiment, track holding mech-anism 51 comprises two hydraulic cylinders for vertically mov-ing the mechanism relative to the machine frame. The mechanism further includes means engaging the track rails. A fluid flow blocking device 52 is mounted in the hydraulic conduit interconnecting the chambers of each of the cylinders of track holding mechanism 51, this blocking device being actuated electromagnetically and the solenoid for the actuation of block-ing device 52 being connected to contact 45 for operation when the contact has reached the illustrated middle position in-dicating the desired level of the track, i.e. the track is held by mechanism 51 at the desired level against further upward movement by tamped ballast. This avoids excess lifting of the track beyond the desired level during tamping. When the tamping tool assembly i5 raised, limit switch 48 will open relay 49, thus opening control switches 57 and blocking device S2.
.. ' 108Z5Zl As indicated by the chain-dotted lines in FIG. 5, the amplifier and switches of the control circuit 41 are mounted on a panel to simplify the operation and possible repairs, the entire panel being replaceable in case of break-downs.
For an operation not contemplated by the invention, a throw-over switch 55 is also mounted on the panel in the connection between amplifier 43 and switch 44, operation of switch 55 cutting out switch 44 and contact 45 from the control circuit and transmitting the error signal from the amplifier directly to servo valves 47 and 50, causing the track to be lifted solely by unit 12 and not by tamping of the ballast.
A master pressure gage 53, which is preferably assoc-iated with a pressure indicator, is mounted in the hydraulic supply conduit for the tamping tool drives so as to make it possible to obtain and control the desired degree of ballast compaction by squeezing of the tools. Master switch 56 in the electrical control circuit is connected to press-ure gage 53, a relay for the actuation of the master switch being responsive to a set maximum pressure to open the master switch and thus to interrupt,a direct circuit controlling hydraulic fluid supply to the tamping tool drives. This direct control circuit is in shunt with switch 44 and con-tact 45 so that ballast tamping ~s continued until the set maximum degree of ballast compaction against the counter pressure of track holding device 51 has been reached after the track has been lifted by jack 24. In its simplest, illustrated form, the master switch is constituted by an adjustable contact associated with the indicator of a con-! tact manometer.
After tamping has been completed, the tamping tool -,.
_g_ ,assembly is raised and opened limit switch 48 will actuate relay 49 so as to interrupt hydraulic fluid flow to the tamping tool drives. The mobile machine is then advanced by a distance of two ties to start the next tamping and leveling cycle.
Fully automatic operation of control 41 may be achieved by connecting the control circuit, and also control l9, if ~ desired, to a suitable programmer 54 operating on an analog - or digital computer basis, thus relieving the operator of any control function and enabling him to concentrate on ad-justing the operating results. Such a programmer will auto-matically control the degree of tamping, the tamping tool reciprocating times and pressures as well as the frequency and/or amplitude of the tamping tool vibrations in response to data transmitted to the programmer by the pressure adjust-ment devices and corresponding to the condition of the ballast. Such data may be stored, for instance, on perfor-ated bands or cards, or magnetic tapes.
The operation of control 41 may be programmed in a variety ways but when programmed according to this invention, jack 22 ceases operation just before tamping has been completed, the delay between terminating the track jacking, i.e. closing valve 47, and tamping,i.e. closing valve 50, being of the order ~f some tenths of seconds to a few seconds, i.e. quite brief.
The control of FIG. 5 is preferably programmed to terminate track jacking before the track has been raised to the desired level and the final track raising stroke against the limit deter-mined by holding mechanism 51 is effected solely by the con-tinuing tamping. In this manner, track lifting unit 12 does not carry the track weight during those final tenths of :
108Z52~
seconds or seconds of surfacing but this weight presses against the ballast during the final tamping. This downward pressure aids in more rapidly and effectively increasing the ballast compaction, and thus improves the quality of the tamped track. This effect may be further increased, if desired, by continuing tamping even after the track has been pressed upwards against holding mechanism 51.
Depending on track conditions, tamping is continued briefly after termination of jacking either until the track level determined by holding mechanism 51 has been reached or even for moments after it has been reached, the interval between termination of jacking and tamping being varied according to conditions. As is Xnown, it may be desired in certain instances, for instance at rail joints, the set track holdlng mechanism 51 slightly above the final desired level for the track to give the track a chance to settle to this level under train traffic immediately subsequent to the sur-facing operation.
A track surfaced with a tamping and leveling machine of the above described structure will be much more uni~ormly tamped than has been possible with conventional machines and will thus assure greater stability of the graded track.
This will make it possible to increase the length of the time intervals between surfacing operation so as to obtain considerable economy in the maintenance of tracks of a high quality.
This application is related to copending Canadian app~ation Serial No. 191,604, filed February 1, 1974.
~0825Zl tween the opposed tools, and an additional vibratory tamp-ing tool arranged for immersion in the ballast adjacent the end of the tie and for reciprocation in a direction trans-verse to the direction of track elongation. With such an arrangement, the ballast is "boxed in" between the tamping tools substantially from the point of intersection of the rail and tie to the end of the tie, thus preventing the outward displacement of ballast during the tamping operation.
However, no control over the leveling of the track or the degree of ballast compaction is possible with such known track tampers because they neither comprise a leveling re-ference nor a tamping control.
It is also known to level track solely by tamping the ballast under the ties. In such track leveling machines, only opposed tamping tools reciprocated in the direction of track elongation are used and a control terminates the tamping operation in response to a reference signal indi-cating the desired track level. If the track must be raised to the desired level through a considerable lifting stroke, 2Q such machines also use independent track lifting mechanisms.
However, controlled uniform ballast compaction cannot be achieved with such machines since the ballast may escape laterally when the tamping pressure in the direction of track elongation exceeds a given degree while, in other track sections, the desired track level has been reached before the ballast has been sufficiently compacted.
Furthermore, it has been proposed to assure the main-tenance of a desired track level even under high tamping pressures by holding the track in position d~ring tamping, the track holding being so controlled that the track will .. ... . . .
' ' . . '. ~ ., ' ~' '; . . . ~
.
108ZSZl not be raised beyond the desired level during tamping. This prevents uncontrolled raising of the track but it does not assure the termination of the tamping when a desired degree of ballast compaction has been reached.
Thus, conventional track surfacing methods and apparatus have not been able to assure a desired, preferably uniform and optimal maximum, degree of ballast compaction under each tie over a long track section. It is, therefore, ~he pri-mary object of this invention to obtain such ballast com-paction, which is particularlyimportant in track sections designed for high-speed trains.
This and other objects are accomplished by the inven-tion in a method of leveling a track in relation to a refer-ence system by holding the track in the leveled position under the control of the reference system in the region of tamping, the ballast being pressed against the held track until it has reached a controlled degree of compaction.
The track is jacked up towards the leveled position and track jacking is terminated tenths of seconds up to several seconds before track tamping has been completed, the bal-last being compacted under the points of intersection of the ties and rails by vibratory pressure exerted upon the ballast under the ties inwardly from the two longitudinal tie edges and preferably from the tie ends. This produces not only a high degree of accuracy in the track level but also on optimally and uniformly compacted ballast bed.
Since tamping proceeds always simultaneously with jacking, track surfacing according to the present invention does not disturb the position of those ballast pieces whose sharp edges or corners bite into the underside of wooden . . .
ties when the track settles on the ballast bed, thus leav-ing the ballast enmeshed with the ties. This is of parti-cular advantage in high-speed traffic sections where the passing trains have strongly settled the track, the method of this invention providing for the track to be lifted during leveling with the conventional track lifting mechanism with-out destroying the intermeshing relationship of the ties and ballast. Tamping while jacking according to the inven-tion, the ballast piec~s remain undistur~ed in~heir re-lationship to the undersides of the ties and are even press-ed further into the undersides when the tamped ballast presses upwardly against the held track after jacking has ceased. This also assures a particularly sensitive approach of the track to the leveled position since the track is not torn out of its settled~osition but progressively p~essed from the settled into the leveled position, which impr3ves the accuracy of the leveling operation.
A mobile track tamping and leveling machine according to the present invention combines a known type of a level-ing reference system and of a tamping tool assembly which comprises not only a pair of opposed vibratory tamping tools -~ but preferably also an additional vibratory tamping tool adjacent the tie end with a track holding device holding the track at the leveled position controlled by the error signal from the reference system. Furthermore, a control regulates the track jacking and the drive means for the re-ciprocation and for the vibration of the tamping tools so that jacking and tamping initially proceed simultaneously but jacking is terminated before ~mping has been completed.
With this combination of structures mounted on the ~... . . . . . .
. , ., , ' ~ -.. ~ . . .
108ZS;21 mobile machine frame, the track will be leveled automatically and the ballast tamping will be terminated automatically when the optimal ballast compaction has been reached, the machine being readily adaptable by the control to differing ballast conditions while assuring long-lasting ballast com-paction.
The above and other objects, advantages and features of the present invention will become more apparent from the following detailed description of a now preferred em-bodiment thereof, taken in conjunction with the single figure of accompanying drawing.
The drawing schematically shows an embodiment of a ballast tamping and track leveling machine with a control circuit 41 for the operation of crib and end tamping tools 8, 9,track lifting and leveling unit 12 and a track holding mechanism 51. As shown in the drawing, the error signal from reference signal pickup and transmitter 6 is transmitted to sum-and-difference amplifier 43 which comprises an adjustable resistance set to indicate the desired value, the error signal being compared with the set value in the amplifier. The com-parison signal is transmitted from amplifier 43 to stepping switch 44 whose switching steps are adjustable. Depending on the adjusbm~ of the switch, contact 45 is actuated in response to the comparison signal received, which contact places the drives for reciprocation of the tamping tools and for track lifting and leveling unit 12 into a state of readiness. When switch 44 moves contact 45 into its lower position, as shown in FIG. 5, which produces a state of readiness for track lifting, switch 42 is operated to transmit the comparison or error signal directly to solenoid valve 47, which preferably is ... . ..
.; .
10825Zl a servo valve. This valve is arranged in the hydraulic supply conduit leading from tank 23 to lifting cylinder 22 and opening thereof permits hydraulic fluid flow to the cy-linder for lifting unit 12 to raise the track in response to the error signal. However, track lifting as well as reciprocation of the tamping tools is effected only when limit switch 48 affixed to the machine frame in the path of the vertical movement of tamping tool assembly 7 is tripped upon lowering of the tamping tools assembly, the limit switch being connected to relay 49 which actuates control switch 46 in the electrical connection between switch 42 and servo valve 47. The relay also actuates control switches 57 for operation of the tamping tools so that, depending on the position of contact 45 controlled by switch 44, servo valve 47 controlling the track lifting or servo valve 50 controlling the tamping tool reciprocation is actuated.
The machine operation is controlled in the following manner:
When the comparison or error signal detected and trans-mitted by amplifier 43 is below the tolerance, i.e. the switching step, set at switch 44, contact 45 connected to switch 44 is in the illustrated upper position, placing the hydraulic supply to the tamping tool drives into a state of readiness. When the error signal surpasses the set tolerancej switch 44 moves contact 45 from its upper end position to its lower end position to close switch 42 and place the hydraulic supply to lifting unit 12 into a state of readiness. Assuming control switches 46 and 57 to be closed upon tripping of limit switch 48 caused by lowering of the tamping tool assembly, servo valve 47 will be opened a ,, , .. . . .
and the track will be raised by unit 12 as long as the error signal value exceeds that of the set switching step and until it is equal thereto, after which, i.e. in the period between the set switching step value and the value of the desired level, servo valve 47 is closed and servo valve 50 remains open for further compaction of the ballast by the squeezing tamping tools after track jacking has been terminated. Closing of valve 47 causes unit 12 to dis-continue lifting the track, the illustrated dump position of valve 47 permitting fluid to flow back from cylinder 22 into tank 23 to allow the track to be further raised by tamping.
Track holding mechanism 51 is mounted in the range of the tamping tool assembly 90 as to prevent the tamped ballast from raising the track above the desired level determined by the reference system 5. In the illustrated embodiment, track holding mech-anism 51 comprises two hydraulic cylinders for vertically mov-ing the mechanism relative to the machine frame. The mechanism further includes means engaging the track rails. A fluid flow blocking device 52 is mounted in the hydraulic conduit interconnecting the chambers of each of the cylinders of track holding mechanism 51, this blocking device being actuated electromagnetically and the solenoid for the actuation of block-ing device 52 being connected to contact 45 for operation when the contact has reached the illustrated middle position in-dicating the desired level of the track, i.e. the track is held by mechanism 51 at the desired level against further upward movement by tamped ballast. This avoids excess lifting of the track beyond the desired level during tamping. When the tamping tool assembly i5 raised, limit switch 48 will open relay 49, thus opening control switches 57 and blocking device S2.
.. ' 108Z5Zl As indicated by the chain-dotted lines in FIG. 5, the amplifier and switches of the control circuit 41 are mounted on a panel to simplify the operation and possible repairs, the entire panel being replaceable in case of break-downs.
For an operation not contemplated by the invention, a throw-over switch 55 is also mounted on the panel in the connection between amplifier 43 and switch 44, operation of switch 55 cutting out switch 44 and contact 45 from the control circuit and transmitting the error signal from the amplifier directly to servo valves 47 and 50, causing the track to be lifted solely by unit 12 and not by tamping of the ballast.
A master pressure gage 53, which is preferably assoc-iated with a pressure indicator, is mounted in the hydraulic supply conduit for the tamping tool drives so as to make it possible to obtain and control the desired degree of ballast compaction by squeezing of the tools. Master switch 56 in the electrical control circuit is connected to press-ure gage 53, a relay for the actuation of the master switch being responsive to a set maximum pressure to open the master switch and thus to interrupt,a direct circuit controlling hydraulic fluid supply to the tamping tool drives. This direct control circuit is in shunt with switch 44 and con-tact 45 so that ballast tamping ~s continued until the set maximum degree of ballast compaction against the counter pressure of track holding device 51 has been reached after the track has been lifted by jack 24. In its simplest, illustrated form, the master switch is constituted by an adjustable contact associated with the indicator of a con-! tact manometer.
After tamping has been completed, the tamping tool -,.
_g_ ,assembly is raised and opened limit switch 48 will actuate relay 49 so as to interrupt hydraulic fluid flow to the tamping tool drives. The mobile machine is then advanced by a distance of two ties to start the next tamping and leveling cycle.
Fully automatic operation of control 41 may be achieved by connecting the control circuit, and also control l9, if ~ desired, to a suitable programmer 54 operating on an analog - or digital computer basis, thus relieving the operator of any control function and enabling him to concentrate on ad-justing the operating results. Such a programmer will auto-matically control the degree of tamping, the tamping tool reciprocating times and pressures as well as the frequency and/or amplitude of the tamping tool vibrations in response to data transmitted to the programmer by the pressure adjust-ment devices and corresponding to the condition of the ballast. Such data may be stored, for instance, on perfor-ated bands or cards, or magnetic tapes.
The operation of control 41 may be programmed in a variety ways but when programmed according to this invention, jack 22 ceases operation just before tamping has been completed, the delay between terminating the track jacking, i.e. closing valve 47, and tamping,i.e. closing valve 50, being of the order ~f some tenths of seconds to a few seconds, i.e. quite brief.
The control of FIG. 5 is preferably programmed to terminate track jacking before the track has been raised to the desired level and the final track raising stroke against the limit deter-mined by holding mechanism 51 is effected solely by the con-tinuing tamping. In this manner, track lifting unit 12 does not carry the track weight during those final tenths of :
108Z52~
seconds or seconds of surfacing but this weight presses against the ballast during the final tamping. This downward pressure aids in more rapidly and effectively increasing the ballast compaction, and thus improves the quality of the tamped track. This effect may be further increased, if desired, by continuing tamping even after the track has been pressed upwards against holding mechanism 51.
Depending on track conditions, tamping is continued briefly after termination of jacking either until the track level determined by holding mechanism 51 has been reached or even for moments after it has been reached, the interval between termination of jacking and tamping being varied according to conditions. As is Xnown, it may be desired in certain instances, for instance at rail joints, the set track holdlng mechanism 51 slightly above the final desired level for the track to give the track a chance to settle to this level under train traffic immediately subsequent to the sur-facing operation.
A track surfaced with a tamping and leveling machine of the above described structure will be much more uni~ormly tamped than has been possible with conventional machines and will thus assure greater stability of the graded track.
This will make it possible to increase the length of the time intervals between surfacing operation so as to obtain considerable economy in the maintenance of tracks of a high quality.
This application is related to copending Canadian app~ation Serial No. 191,604, filed February 1, 1974.
Claims (7)
1. A method of leveling a track consisting of rails mounted on ties by jacking up the track and tamping ballast by vibratory pressure under the ties, the track being level-ed in relation to a reference system, comprising the steps of (1) simultaneously jacking and tamping the track, (2) terminating track jacking tenths of seconds to several seconds before tamping has been completed, and (3) completing tamping while holding the track in a desired position of a high degree of accuracy under the control of the reference system in the region of tamping until tamping has been terminated at a desired degree of ballast compaction.
2. The method of claim 1, wherein track jacking is terminated before the track has been lifted to the held position.
3. The method of claim 1, wherein track jacking is terminated when the track has been lifted to the held position.
4. Apparatus for leveling a track consisting of rails mounted on ties and tamping ballast thereunder, comprising the combination of (1) a reference system in relation to which the track is leveled, (2) jacking means for lifting the track, (3) tamping means for tamping the ballast by vibratory pressure, (4) control means for operating the jacking and tamping means, the control means including (a) a control for simultaneously jacking and tamping the track, and (b) a control for terminating track jacking before tamping has been completed, (5) means in the region of the tamping means for holding the track in a desired position of a high degree of accuracy under the control of the reference system, and (6) means for locking the holding means in said position under the control of the reference system.
5. The apparatus of claim 4, wherein the track holding means is positioned above the point of tamping in the region of the tamping means.
6. The apparatus of claim 4, wherein the tamping means comprises a vertically movable tamping tool assembly includ-ing a pair of opposed vibratory tamping tools arranged for immersion in the cribs adjacent a tie and for reciprocation in the direction of track elongation, with the tie posi-tioned between the opposed tools, an additonal vibratory tamping tool arranged for immersion in the ballast adjacent the end of the tie and for reciprocation in a direction transverse of the direction of track elongation, and drive means for the reciprocation and for the vibration of the tamping tools, the control means operating the drive means.
7. The apparatus of claim 6, further comprising a control for regulating the degree of ballast compaction, the control comprising regulating means for the drive means, the regulating means comprising separate governors assoc-iated respectively with the drive means for the opposed tamping tools and the drive means for the additional tamping tools.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA250,281A CA1082521A (en) | 1976-04-14 | 1976-04-14 | Method and apparatus for obtaining a controlled degree of ballast compaction in the tamping and leveling of a track |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA250,281A CA1082521A (en) | 1976-04-14 | 1976-04-14 | Method and apparatus for obtaining a controlled degree of ballast compaction in the tamping and leveling of a track |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1082521A true CA1082521A (en) | 1980-07-29 |
Family
ID=4105716
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA250,281A Expired CA1082521A (en) | 1976-04-14 | 1976-04-14 | Method and apparatus for obtaining a controlled degree of ballast compaction in the tamping and leveling of a track |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1082521A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113195830A (en) * | 2018-12-27 | 2021-07-30 | 普拉塞-陶伊尔铁路机械出口股份有限公司 | Method for processing ballast track and track-building machine |
-
1976
- 1976-04-14 CA CA250,281A patent/CA1082521A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113195830A (en) * | 2018-12-27 | 2021-07-30 | 普拉塞-陶伊尔铁路机械出口股份有限公司 | Method for processing ballast track and track-building machine |
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| MKEX | Expiry |