US3545384A

US3545384A - Method and apparatus for correcting the position of a track

Info

Publication number: US3545384A
Application number: US729093A
Authority: US
Inventors: Franz Plasser; Josef Theurer
Original assignee: Individual
Current assignee: Franz Plasser Bahnbaumaschinen Industrie GmbH
Priority date: 1967-05-22
Filing date: 1968-05-14
Publication date: 1970-12-08
Anticipated expiration: 1987-12-08
Also published as: JPS4911885B1; FR1568484A

Description

United States Patent Inventors Franz Plasser;

Josef Theurer, Johannesgasse 3, Vienna, Austria Appl. No. 729,093 Filed May 14,1968 Patented Dec. 8, 1970 Priority May 22, 1967 Austria Nos. A4785/67 and A4784/67 METHOD AND APPARATUS FOR CORRECTING THE POSITION OF A TRACK 28 Claims, 24 Drawing Figs.

US. Cl. 104/7, 1 104/8, 104/12 Int. Cl. EOIb 27/17, E01 b 3 3/02 Field of Search .t 104/7, 7(8), 8, l2

[56] References Cited UNITED STATES PATENTS 3,269,017 8/1966 Stewart 104/12 3,401,642 9/ l 968 Fisher l04/8 3,459,136 8/1969 St. John [04/8 Primary Examiner-Arthur L. La Point Assistant Examiner-:Richard A. Bertsch A;t0rney Kurt Kelman ABSTRACT: The position of a track is corrected in two phases. In the first phase, the track is moved by a track engaging means and this movement is terminated before the correct track position has been reached. The movement of the track to the correct position is then continued in a second phase solely by tamping the ballast.

PATEN'TED nan 8I970 3.545; 384

SHEET 3 OF 3 INVENTORS BY MN @am BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates to a method and apparatus for grading and/or lining a track in relation to a reference system associated with at least one rail of the track. Such track correction is accomplished by moving the track until the correct track position is indicated by an indicating element cooperating with a reference system, the indicating element moving in unison with the rail to be moved for correction.

A variety of machines of this type are known and comprise not only such a reference system but also track correction means arranged for engagement with the rail and for moving the rail, and means for tamping the rail to fix the same in the corrected position. The reference system may be constituted by reference lines, such as tensioned flexible elongated members or beams of electromagnetic.radiation, i.e. wires or light beams, but it may also consist of rigid parts, such as rods and the like, whose position in relation to the track may be varied, if desired, in any predetermined manner.

In the conventional track grading and/or lining procedures, the track engaging means were operated to move the track vertically and/or laterally until the cooperating indicating element and reference system indicated the correct track position to have been attained. At this point, a controlsignal was usually generated by the cooperation of the reference system with the indicating element to terminate the operation of the track engagingmeans.

During and/or after the track correction movement, the ballast was tamped at the point of correction to fix the track in the corrected position. To assure a long lasting fixation of the track in its corrected position, it is desirable to compact the ballast on which the track rests as densely as possible, requiring high tamping pressures. Such high-pressure ballast compaction tends to cause further movement of the track upwards or sidewards, depending on the direction of the tamping pressure. Thus, in the conventional procedure wherein the ballast was tamped after the track had reached its corrected position, the additional tamping causedfurther movement of the track out of its corrected position. In an effort to avoid this and thus to minimize faulty track positioning, the tamping pressure was so controlled that the tools worked under less than maximally attainable pressures. This, on the other hand, unfavorably influenced ballast compaction and thusreduced the quality of the tamping since maximal tamping pressures, particularly in the final tamping phase, are desirable to obtain maximum compaction of the ballast.

Attempts at such tamping pressure regulation have been on a been on a hit-and -miss basis since it is exceedingly difficult, if not impossible to regulate the tamping pressure after the track position has been corrected so as to avoid furthermovement of the track but still to keep it high enough to produce high-quality tamping. This regulation is particularlydifficult since ballast density varies considerably from track point to track point so that the same tamping pressure has different results at different points. a

This phenomenon holds for grading wherein the ballast is tamped underneath the tie to fix the graded track in the correct position, such compaction causing the track to rise slightly under the pressure of the compacted ballast, as well as for lining wherein the ballast is tamped only on that side of the Y track from which it has been moved, such ballast compaction at one end of the track ties preventing the tendency of the track to return to its original position after the track shifting means has been released and the resiliency of the track would snap it back if this were not prevented by the compacted ballast at that side.

Thus, the tamping pressure selection and regulation has been a very difiicult problem in conventional track grading and/or lining operations wherein the track is moved into its correct position by track correction means and fixed in this position by tamping. Errors have resulted either in the tion is indicated. The movement of therail by the rail engaging,

direction of inaccurate track positioning due to excess tamping pressure or low quality of tamping due to low tamping pressure.

' It is a primary object of the present invention to avoid the above and other disadvantages, to utilize maximum tamping pressures in track correction operations and to use these pressures to move the track during a final correction phase into the correct position without the arbitrary regulation of the tamping pressure at different track points.

The above and other objects are accomplished in accordance with this invention by moving the track rail, with which the reference system is associated and with which the indicating element moving in unison with the rail cooperates to indicate the correct track position, by rail engaging means, terminating this movement before the correct track position has been reached, and continuing the movement of the rail solely by the tamping of the ballast until the correct track posi means is terminated in response to a predetermined position of the indicating element in respect of the reference system.

In track grading and/or lining machines of the abovedescribed type, the invention provides means responsive to a first predetermined position of the indicating element in respect of the reference system for terminating the movement of the rail by the track correction means before the correct position of the track has been reached, and means for actuating the tamping means for moving the rail into the correct position by tamping after the movement by the track correction means has been terminated. Means responsive to a second predetermined position of the indicating element in respect of the reference system terminates actuation of the tamping means, the second predetermined position indicating the correct track position BRIEF DESCRIPTION OF DRAWING The above and other objects, advantages and features of the present invention will be better understood by reference to the following detailed description of certain now preferred embodiments thereof, given for purposes of illustration and not as a limitation, taken in conjunction with the accompanying drawing wherein:

FIG. 1 is a schematic side view of a track correction apparatus according to this invention;

FIG. 1a is a top view ofFIG. 1;

FIG. 2 is a side view of one embodiment of an indicating element of the reference system used in the apparatus;

' FIG. 2a is a front view of FIG. 2;

FIG. 3 shows a control circuit: actuated by a signal generated by the indicating element of Flg FIG. 2 for actuating the track grading and tamping means of the apparatus;

FIGS. 4 and 4a illustrate the practical advantage obtained by grading with the apparatus of FIGS. 2 and 3;

FIG. 5 schematically illustrates a reference system according to the invention and using a vertically movable reference line;

FIG. 6schematically illustrates a reference system according to the invention and using a spotboard;

FIG. 7 illustrates a detail of track correction means for laterally moving the track in a lining operation;

FIG. 8 shows a control circuit actuated by the moving means of FIG. 7; and

FIGS. 9 to 13 show schematically in side, top and front views various modifications of a reference system according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The illustrated track correction apparatus is designed to correct the vertical as wellas the lateral position of a track, ie. it is useful for track grading and lining. Conventional apparatus of this type includes a machine frame 1 which is mounted on

trucks

2 and 3 for mobility on

rails

4, 4 of the track to be corrected. The track includes ties 5 supporting the rails on ballast (not shown).

This conventional mobile track grading and lining machine has mounted on the machine frame 1 any suitable means 6 for engaging the track rails and moving the same laterally at track point R. Laterally spaced outwardly of the ends of the ties 5 and in lateral alignment with the track moving means 6 are a pair of

ballast surface tampers

7, 7 which are vertically adjustably mounted on the machine frame, one or the other of these tampers being selectively moved into surface contact with the ballast for tamping the opposite to the side towards which the track is to be moved. In this manner, tamping of the ballast by this one tamper will effectively assist in moving the track in the opposite direction.

The front end of the machine frame carries a vertically adjustable track lifting means 8 of generally conventional structure, which includes a pair of rail gripping elements 9 for each rail. Tamping means 10, as shown, for instance, in our U.S. Pat. No. 3,372,651, is mounted adjacent the lifting the lifting means to tamp pairs of ties 5 adjacent the grading point and to fix the ties in the graded position.

The track position is corrected, i.e. the track is graded and/or lined, in relation to a reference system associated with at least one rail of the track until the correct position of the track is indicated by an indicating element cooperating with a reference element of the system. A variety of such elements will be described hereinafter, including reference elements consisting of beams of electromagnetic radiation, such as light beams, and tensioned flexible elongated members, such as tensioned wires.

In the embodiment of FIGS. 1 and 1a, the reference system for lateral alignment by means of track moving means 6 includes two reference lines of different lengths, which may be considered as chords of an arc, i.e. a longer chord 11 and a shorter chord 12 which is half the length of chord 11. The ordinates of the chords are compared at the measuring point M, and the track is moved at point R, i.e. at the forward end of the shorter chord 12 until the ordinate of chord 12 corresponds with a parameter obtained at this point from the ordinate of chord II. The ends of the reference chords are anchored to bogies 13, l4, l5 and 16 which are coupled to machine frame 1 by means of telescoping rods or the like.

The reference system for vertical alignment or grading by means of track lifting means 8,9 includes a reference line 17 which is associated with one of the rails and is parallel to the correct position of the rail to serve as a reference element in respect of which the rail is to be graded. The illustrated reference line is a beam of electromagnetic radiation, such as light, which passes between sender (or receiver) 18 and receiver (or sender) 20. The reference line cooperates with an indicating element 19 which is a spotboard movable in unison with the rail into the path of the beam 17 to indicate the correct position of the rail.

As shown in FIG. la, the track liner may also carry an indicator 19a extending transversely of the track and showing the track superelevation. Pendulum indicators of this type, for instance, are very well known, and the track elevation is adjusted with such indicators by using one rail of the track as the fixed reference in respect of which the other rail is lifted to determine the superelevation of the track.

In such an arrangement in accordance with the invention, the indicator may so control the track lifting operation that the other rail is raised only by tamping.

The forward bogie 13, to which the forward end of long chord 11 is anchored and which carries also the forward end of the reference line 17, is stationed in a track portion to be corrected. The indicating element 19 rests on a rod supported on a point of the track to be corrected whereby the element 19 moves in unison with the rail when the latter is lifted by by hydraulically operated rail lifting means 8,9. When the top edge of element 19 enters the path of light beam 17, the rail has reached its correct grade and this element may, therefore, be used as a signal generator to control the movement of the rail. The rear end 20 of reference line 17 is supported on a bogie 21 which rests on a graded portion of the track behind the tamping means 10.

All of the above-described structure is conventional and has, therefore, been shown and described only broadly for purposes of a better understanding of the environment of the present invention.

FIGS. 2 and 2a and 3 show one embodiment of an indicating element and an associated control circuit useful in the practice of this invention. In this embodiment, the indicating element is a spotboard having a fixed part 22 which is mounted on a rod, as shown in FIG. 1, which is supported on rail 4 and moves upwardly towards reference element 17 in unison with the rail in the direction of the arrow shown in FIG. 2 when the rail is lifted by

means

8,9. Fixed spotboard part 22 carries a part 23 which is movable in respect thereto in the direction of movement of the spotboard, and which has an upper sensing edge for cooperation with the beam 17. The sensing edge of movable part 23 may be moved upwardly to be spaced adjustably from the upper edge of the fixed part 22 by a distance x. When the movable part has been extended in the illustrated manner by distance x, the sensing edge of the movable part contacts beam 17 first, whereupon the movable part may be retracted so that its sensing edge no longer extends above the upper edge of the fixed part, and the upper edge of the fixed part will then contact beam 17 as the spotboard moves further upwards in unison with the rail whereon it is supported and which is being graded. The movement of the movable part 23 is hydraulically or pneumatically actuated in the illustrated embodiment, a pressure fluid cylinder 24 being mounted on the fixed spotboard part and a piston 25 moving in the cylinder and supporting the movable part.

Spotboards with an adjustable upper edge are also shown in our U.S. Pat. No. 3,363,582, and any such devices are useful for the present invention.

The control circuit for the track grading operation with the aid of the spotboard of FIG. 2 is shown in FIG. 3. The pressure fluid supply for the pressure fluid motor 24, 25 is part of the pressure fluid circuit used for the operation of the hydraulically operated rail lifting means 8, 9 and tamping means 10. At the beginning of the grading operation, control S opens valve 28 to deliver pressure fluid to hydraulic motor 26 of the track lifting means and valve 29 to hydraulic motor 27 for reciprocating the tamping tools of tamping means 10. Thus, the rail is lifted, tamping of the ties under the lifted rail is begun and, simultaneously, pressure fluid is also delivered to motor 24,25 to extend the movable part of this spotboard as it approaches the reference beam-l7. As soon as the extended sensing edge of movable spotboard part 23 contacts the beam, a first signal is generated and sent to receiver E which signal is amplified by amplifier V, and the amplified signal is sent to control S which includes a series of relays. This causes the control S to close valve 28, thus interrupting the operation of the track lifting means before the rail has attained the correct grade. Simultaneously, control S reverses the flow of pressure fluid into cylinder 24, i.e. it delivers the fluid to the upper instead of the lower chamber, thus retracting the movable part 23 away from reference beam 17. However, valve 29 remains open and the tamping means continues to operate to tamp the ballast below the lifted ties of the track. This tamping of the ballast causes the track to be raised further until the upper edge of the fixed spotboard part contacts beam 17 to generate a second signal. Contact between the fixed upper edge of the spotboard and the reference beam indicates that the rail has reached the correct grade. The second signal is also received at E, amplified by V and operates the relays of control S to close valve 29 and thus to discontinue tamping.

As is well known, the hydraulic pressure may be used not only to reciprocate the opposing pairs of the tamping tools but also to vibrate them and to move the tamping tool carrier up and down to immerse the tools in the ballast and to remove them therefrom.

In the above described operation, the first grading phase is effectuated by the rail lifting means until the firstsignal is generated, whereupon the second grading phase begins to lift the rail by the distance x to the correct grade only by means of tamping.

In FIG. 3, the full lines of the circuit show electrical control lines while the dash-dot lines indicate pressure fluid conduits.

The advantage of such a two-phase track correction operation is illustrated in FIGS. 4 and 4a, with FIG. 4 showing the conventional operation while FIG. 4a illustrates the grading operation according to the present invention.

Conventionally, rail lifting means 9 were used to lift the rail 4 with ties 5 the desired distance ain respect of reference line 17. Simultaneously and for a short period thereafter, tamping was effectuated at 10 at a track point immediatelyadjacent the track lifting point. The hydraulically operated tamping tools reached their highest pressure and corresponding degree of ballast compaction towards the end of the operation when the ties had been lifted to the desired grade by lifting means 9. However, this strong compaction of the ballast forced the ties higher and above the desiredgrade so that the track received a hump indicated by the upwardly pointed arrow at the tamped tie.

In contrast thereto and as shown-in FIG. 4a, the rail is lifted in the first phase by lifting means 9 only by a distance xi, the remaining distance x being covered in the second phase by tamping only so that the graded rail will be accurately and evenly corrected in relation to the reference line 17 In the above-described embodiment, a part of the indicating element of the referencesyste m'is spaced from the reference element thereof after the first phase has been terminated, this spacing corresponding to the distance x required to lift the track to the correct position solely by tamping. However, the same result may be accomplished by spacing at least a portion of the reference element from the indicating element by this distance x so that a second control signal will be generated when the indicating element has risen in unison with the rail by that distance to the new level of the reference element. An embodiment of such a structure is shown in FIG. 5.

In this embodiment, too, the reference system includesan indicating element 19 and a cooperating reference element 17. The reference element is a tensioned wire 17 trained over

pulleys

30,30. A means 31 for moving a portion of the a reference line 17 in respect of the spotboard 19 is mounted adjacent each end of the reference line, the illustrated reference line moving means being a lever arm arranged to press against the tensioned wire in a direction opposite to that of the movement of the spotboard (see arrow). The lever arm 31 is pivoted against the wire 17 by a hydraulic or pneumatic motor 32 when this motor is operated in a manner equivalent to that of motor 24,25 of FIG. 3, the lever arm 31. being normally held in the upper position shown in full lines by the bias of return spring 33.

If only a single lever is provided (for instance, the lever at the right in FIG. 5), the tensioned wire will assume the inclined position 17a shown in broken lines when the lever is depressed. However, if the illustrated pair of levers is mounted adjacent each end of the tensioned wire, it will assume the depressed position shown in dash-dot lines at 17b when both levers are moved down simultaneously. In either case, the portion of the reference element cooperating with indicating element 19 is moved towards the indicating element by distance x. Contact between the depressed reference element and the rising indicating element generates the first signal in the same manner as described hereinabove in connection with FIG. 3, whereupon the reference element is raised by distance x the second signal being generated upon contact of the indicating element 19 with the raised reference element to terminate the second grading phase.

Obviously, any other suitable means may be used to change the distance between the indicating element and the reference element. For instance. the pulleys could he vertically adjustably mounted so as to move the reference. line into selected distances from the indicating element.

FIG. 6 shows yet another embodiment of the present invention. In this embodiment, the reference element is a sighting line 17 emanating from surveying instrument 18 mounted on front bogie 13. The sighting line 17 is directed towards spotboard 34 which carries a series of superposed markers 35 each having a width corresponding to distance x. (For a better illustration of this spotboard, it has also been shown in front view in FIG. 6). The spotboard is glidably attached in bearings on the pressure fluid cylinder 8 of the lifting means, the piston in the cylinder carrying the rail engaging clamp 9. In this manner, the indicating element 34 moves in unison with the rail 4 when the same is lifted, a lifting device of this type being shown, for instance, in our US. Pat. Nos. 2,847,943 or 3,146,727.

When the surveyor at instrument 18 projects the sighting line against one marker 35, he discontinues the operation of

hydraulic lifting motor

8,9, and when the sighting line registers with the next marker, which indicates the correct grade, tamping is discontinued, too. 20

Obviously, instrument 18 may be a sender of a beam of electromagnetic radiation andthe markers may be photosensitive cells, for instance, so that successive signals will be automatically generated in the previously described manner when the reference beam hits successive markers during the upward movement of the spotboard, as shown in FIG. 13.

An embodiment of the invention showing the same applied to track lining is shown in FIGS. 7 and 8. The track alignment device hasbeen only partially shown since it is fully described in our US. Pat. No. 3,3l4,373. It includes a transversely extending rotatable threaded shaft 36 carrying a nut 37 which constitutes an indicating element movable in unison with the rail transversely of the track elongation, and which cooperates with the reference line 12 (see I FIG. 1a). The nut has a bifurcated portion 38 constituting sensing means on each side of the reference line to determine when the reference line is free of contact with the sensing means, i.e. the desired alignment has been accomplished. No further description of this alignment method is required in view of the full description in our prior patent.

According to the present invention, the indicating element part 38 .is movable in respect of the fixed indicating element part 37 by means of

hydraulic motor

39,40, being first extended forwardly by distance x towards the reference line (see broken lines) in a manner quite similar to that described in connection with the grading method of FIG. 3. In this manner, a first signal is produced in the extended position of the indicating element sensing part and a second signal is generated in the retracted position of this part, the first signal causing termination of the operation of the track shifting means and the second signal terminating the tamping. In principle, therefore, lateral alignment according to this invention operates in a the samemanner as vertical grading, the difference being that the indicating element extends toward the reference element ina horizontal plane transversely of the track for lining while it extends in a vertical plane perpendicularly to the track for grading, i.e. always in the direction of movement of the indicating element in unisonwith the rail whose position is to be corrected.

This analogous operation is shown in the circuit diagram of FIG. 8 whichis similar to that of FIG. 3. In other words, the

, pressure. fluid supplyfor the

pressure fluid motor

39,40 is part of the pressure fluid circuit (shown in dash-dot lines) used for operation of the hydraulically operated rail shifting means 6 and surface tamping means 7. At the beginning of the lining operation, control S opens

valves

44,45 and 46 to deliver pressure fluid to the hydraulic motor of the track shifting means 6 and to the vibrator of surface tamper 7, branch line 43 simultaneously delivering pressure fluid to

hydraulic motor

39,40 to with the forwardly extended bifurcated sensing part 38, a first signal is generated and sent to receiver S which is amplified by amplifier V, and the amplified signal is sent to control S which includes a series of relays, the electrical circuit lines being shown in full lines. This causes the control S to close valve 45, thus interrupting the operation of the track shifting means 6 before the rail has attained the correct alignment. Simultaneously, control S removes the pressure from cylinder 39, thus permitting retraction of movable sensing part 38 under the bias of spring 42 away from reference line 12 into the position shown in full lines in FIG. 7. However, valve 46 remains open and the surface tamper continues to operate to tamp the ballast next to the end of the tie, causing the track to be shifted further (towards the right, as seen in FIG. 8) until the reference line 12 is again out of contact with the retracted sensing part 38, which indicates the correct alignment and generates a second signal terminating tamping, i.e. closing valve 46. Thus, the two-phase alignment proceeds in the same manner as the previously describedtwo-phase grading, the second phase of the alignment being effectuated solely by tamping.

The side view of FIG. 9 and the top view of FIG. 10 show respective embodiments useful for grading and lining, wherein the reference system includes a plurality of successive reference elements cooperating with a single indicating element moving in unison with the rail to be corrected.

In the grading arrangement of FIG. 9, two superposed reference beams l7, 17 are spaced apart by distance x, each beam extending between a sender (or receiver) l8", l8 and a receiver (or sender) 20', 20, the ends 18, 18 of the beam being at front bogie 13 while the ends 20, 20 are mounted on the machine frame 1. The spotboard 19 moves upwardly with rail 4, being glidably journaled at the front end of the frame. As shown in FIGS. 9a, 9b and 9c, the reference lines are superposed in the direction of movement of the indicating element 19 so that the sensing edge of the element 19 will generate a first signal when it contacts-the lower reference line and a second signal when it contacts the upper reference line spaced from the lower line by distance x. The operation of these signals has been explained hereinabove. As shown in FIGS. 9b and 9c, the superposed reference lines may also be laterally staggered so that a stepped edge of the indicating element reachcsfirst the one and then the other line, the distance x then being a function of the distance y between the reference lines and the distance z between the stepped edge portions of the indicating element. Thus, referring to FIG. 9c, the distance x between the reference lines is y-Z.

The identical conditions prevail in the lining arrangement of FIG. 10, except that the two reference lines are in a horizontal plane transversely of the track.

The modifications shown in FIGS. 11 and 12, with illustrative FIGS. Ila, 11b and 110, as well as 1211, are substantially the same as those of the corresponding FIGS. 9 and 10, except that the two reference lines are constituted by different physical embodiments, i.e. line 17' is a light beam, as in the previously described embodiment, while line 17 is a tensioned wire extending between

pulleys

30,30, as in the embodiment of FIG. 5. The operation of these modifications is obvious from the above description.

While the method and apparatus have been described in connection with a number of specific embodiments, it will be obvious to those skilled in this art, particularly after benefiting from the present teaching, that many variations and modifications are possible without departing from the spirit and scope thereof. In principle, it deals with a track grading or lining operation wherein the track is moved by a track engaging means in a first phase and is moved into the correct position in a second phase solely by tamping. To terminate the operation of the track engaging means, a first signal is generated, and the tamping is discontinued in response to the second signal indicating that the correct track position has been reached.

For instance, the present invention is also useful in a method of lifting one rail in relation to the other rail by means of a transversely extending indicator of the superelevation, such as disclosed in our US. Pat. Nos. 3,1 1 1,908 or 3,l26,640, for instance. In this case, the transverse indicator whose indicating element moves in unison with the other rail, which constitutes the fixed reference, is arranged to generate a first signal terminating the operation of the rail lifting jack while the final phase of the rail lifting to the desired grade is effectuated solely by tamping, this phase being discontinued by a second signal in a manner analogous to that described in connection with the illustrated embodiments.

We claim:

I. In a method of correcting the level of a track in relation to a reference system associated with at least one rail of the track until the correct level is indicated by an indicating element cooperating with the reference system, comprising the steps of engaging the rail with a rail engaging means, and upwardly moving the rail with said means, the improvement of terminating the movement of the rail by said means before the correct level has been reached, and continuing the movement of the rail solely by tamping ballast under the rail until the indicating element indicates the correct level, the tamped ballast fixing the rail at said level.

2. In the method of claim 1, wherein the movement of the rail by said means is terminated in response to a predetermined position of the indicating element in respect of the reference system.

3. In the method of claim 2, wherein the indicating element is moved with the rail in respect of the reference system, a first signal is generated in said predetermined position, said first signal actuates the termination of the movement of the rail by said means, a second signal is generated when the correct level has been reached, and said second signal actuates the termination of the tamping.

4. In the method of claim 3, wherein the second signal is generated by another predetermined position of said indicating element in respect of the reference system.

5. In the method of claim 3, wherein the second signal is generated by a predetermined position of a part of said indicating element in respect of the reference system.

6. In the method of claim 3, comprising the further step of spacing the indicating element from said predetermined position in respect of the reference system, the spacing corresponding to the distance of correction to be effectuated solely by tamping.

7. In the method of claim 6, wherein the spacing is effectuated simultaneously with the production of the first signal.

8. In the method of claim 6, wherein the spacing is effectuated by moving at least a part of the indicating element in respect of the reference system.

9. In the method of claim 6, wherein said spacing is effectuated by moving at least a part of the reference system in respect of the indicating element.

10. In the method of claim I, wherein the reference system includes a reference line and the indicating element cooperates with the reference line, and the movement of the rail by said means is terminated when the indicating element moves with the rail into a first predetermined position in respect of the reference line, said first predetermined position deviating from the correct level by the distance by which the rail is to be moved solely by tamping.

11. In an apparatus for correcting the level of a track, comprising a reference system associated with at least one rail of the track, an indicating element cooperating with the reference system and moving in unison with the rail in respect of the reference system to indicate the level of the track, track correction means arranged for engagement with the rail and for moving the rail, and means for tamping the rail to fix the rail in the corrected position, the improvement of means responsive to a first predetermined position of the indicating element in respect of the reference system for terminating the movement of the rail by the track correction means before the correct level of the track has been reached, and means for actuating the tamping means for moving the rail to said correct contact with said reference line.

correction means has been terminated.

12. In the apparatus of claim 11, further comprising means responsive to a second predeterminedposition of the indicating element in respect of the reference system for terminating the actuation of the tamping means, said second predetermined position indicating the correct track position.

13. In the apparatus of claim '12, wherein the indicating element includes a succession -of parts spaced apart in the direction of movement, of "the indicating element and cooperating with the referencesystem for generating a succession of signals corresponding to said predetermined positions.

14. In the apparatus of claim 13, wherein said indicating element parts are photosensitive cells. r

15. In the apparatus of claim 13, wherein theindicating element parts are sensing edges and said reference system includes a reference line arranged for cooperation with said sensing edges.

16. In an apparatus for correcting the level of a track, comprising a reference system'associatedwith at least one rail of the track, an indicating element cooperating with the reference system and moving in unison with the rail in respect of the reference system to indicate the level of the track, track correction means arranged for engagement with the rail and for moving the rail, and means for tamping the railto fix the rail in the corrected position, the improvement of means responsive to a first predetermined position of the indicating element in respect of the reference system for terminating the movement of the rail by the track correction means before the correct level of the trackhas been reached, meansjfor actuating thetamping means for moving the rail to said correct level by tamping after the movementof the rail by the track correction means has been terminated, and means responsive to a second predetermined position of the indicating element in respect of the reference system for terminating the actuation of the tamping means, said second predetermined position indicating the correct track level, the indicating element including a-succession of sensing edges spaced apart in the direction of movement of the indicating element and cooperating with the'reference system for generating a succession of signals corresponding to said predetermined positions, said reference system including a reference line arranged for cooperation with said sensing edges, and a first oneof said sensing edges being movable and generating a first one of said signals upon 17. In the apparatus of claim 16, wherein the indicating element comprises a fixed part carrying the movable sensing edge for movement in the direction of the movement of the indicating element and perpendicularly to the sensing edges, and the fixed indicating element part carries a second sensing edge parallel to the first sensing edge and arranged for cooperation with said reference line when the first sensing edge has been moved in the direction of movement of the indicating element behind the second sensing edge.

18. In the apparatus of claim 17, further comprising a drive for moving the movable sensing edge, said drive being actuindicating the element sensing edge being part of said pressure fluid system, the pressure fluid operated actuationof thetrack correction means causing the movement of the movable sensing edge outwardly of the fixed part of the indicating element in the direction of movement of the indicating element,

and the contact of the first sensing edge with the reference line generating-a signal terminating the'actuation .or the track correction means andcausing the 'movable sensing edge to be retracted inwardly of the second sensingedge on the fixed part of the indicating element.

21. In the apparatus of claim 11, wherein the reference system comprises a succession of reference lines arranged in the direction of movement of the indicating element, said positions of the indicating element in respect of the reference system being predetermined by the successive cooperation thereof with the successive reference lines.

22. In the apparatus of claim 21, wherein a first one of said reference lines in the direction of movement of the indicating element is a beam ofelectromagnetic radiation, and a second one of said reference lines is a tensioned flexible elongated member.

23. In an apparatus for correcting the level of a track, comprising a referencesystem associated with at least one rail of the track, an indicating element cooperating with the reference system and moving in unison with the rail in respect of the reference system to indicate tlhe level of the track, track correction means arrangedfor engagement with the rail and for moving the rail, and means for tamping the rail to fix the rail in the corrected position, the improvement of means responsive to a first predetermined position of the indicating element in respect of the reference system for terminating the movement of the rail by the track correction means before the correct level of the track has been reached, and means for ac tuating the tamping means for moving the rail to said correct level by tamping after the movement of the rail by the track correction means has been terminated, the reference system comprising a succession of reference lines arranged in the direction of movement of the indicating element, said positions of the indicating element in respect of the reference system being predetermined by the successive cooperation thereof with the successive reference lines, the indicating element carrying a succession of sensing edges staggered in the direction of movement of the indicating element, and each of said sensing edges is arranged to cooperatewith a successive one of said reference lines during the movement of the indicating element.

24. In the apparatus of claim 111, wherein the reference system includes :a reference line having at least a portion movably spaced from the indicating element, said positions of the indicating'element in respect of the reference system being predetermined by the successive cooperation of the movable.

reference line portion withthe indicating element, successive cooperation of the indicating element and movable reference line portion generating successive signals to terminate actuation of the rail engaging and of thetamping means.

25. In an apparatus for correcting the level of a track, comprising a referencesystem associated with at least one rail of the track, an indicating element cooperating with the reference system and moving in unison with the rail in respect of the reference systemto indicate the level of the track, track correction means arranged. for engagement with the rail and for moving the rail, and means for tamping. the rail to fix the rail in the corrected position, the improvement of means responsiveto a first predetermined position of the indicating 'elementin respect of the reference system for terminating the movement of the railby the track correction means before the correct level of the track has been reached, means for actuating thetamping means for moving the rail to said correct level by tamping after the movement of the rail by the track correction flmeans has been terminated, the reference system including a reference line having at least a portion movably spaced from the indicating element, said positions of the indicating'element in respect of the reference system being predetermined by the successive. cooperation of the movable reference lineportion with the indicating element, successive cooperation of the indicating element and movable reference line portion generating successive signals to terminate actuation of the rail engaging and of the tamping means, and means for moving said reference line portion in respect of the indicating element, a first cooperation of said reference line portion with the indicating element generating said signal terminating the actuation of the track correction, means and simultaneously causing the moving means to move the reference line portion away and spaced from the indicating element in the direction of movement of the indicating element, the reference line being a tensioned flexible elongated member, and said moving means being an arm arranged to press against the elongated member in a direction opposite to that of the movement of the indicating element.

26. In the apparatus of claim 11, wherein the indicating element is a spotboard carrying at least two markers, and the reference system includes a sighting line directed and ending at said spotboard, said markers generating a first signal terminating the actuation of the track correction means when the sighting line cooperates with a first one of said markers, and a second signal terminating the actuation of the tamping means when the sighting line cooperates with a second one of said markers indicating the correct track position.

27. In the apparatus of claim 26, said markers being photosensitive cells and said sighting line before a beam of electromagnetic radiation. t

28. In an apparatus for correcting the level of a track, comprising a reference system associated with at least one rail of the track, an indicating element cooperating with the reference system and moving in unison with the rail in respect of the reference system to indicate the level of the track, track correction means arranged for engagement with the rail and for moving the rail, and means for tamping the rail to fix the rail in the corrected position, the improvement of means responsive to a first predetermined position of the indicating element in respect of the reference system for terminating the movement of the rail by the track correction means before the correct level of the track has been reached, and means for actuating the tamping means for moving the rail to said correct level by tamping after the movement of the rail by the track correction means has been terminated, said indicating element extending transversely of the track to indicate the track superelevation, the reference system including one of the track rails in respect of which the other track rail is to be moved into the correct position