Track Tamping And Leveling Machine

Abstract

A track tamping and leveling machine with a track tamping unit, a track lifting unit and a reference system for the leveling operation comprises a continuously adjustable electrical track level indicator. The indicator has one indicator part in constant connection with the tensioned reference wire of the reference system and another part in connection with the track to produce a control signal corresponding to the track level prevailing at the track point whereto the other indicator part is connected. A continuously adjustable control device for the track lifting unit drive is electrically connected to the indicator and receives the control signals to adjust the device and correspondingly actuate the drive for the track lifting unit.

Description

The present invention relates to a track tamping and leveling machine which comprises a machine frame mounted for mobility on the track for moving from a previously leveled track section towards a track section to be leveled, vertically adjustable track tamping tools and a track lifting unit mounted on the machine frame, a drive for raising the track lifting unit, and a reference system in respect of which the track is leveled, the reference system including a tensioned reference wire extending from the leveled track section to the track section to be leveled.

Known machines of this type have a sensor which, upon contact with the reference wire, actuates an electrical control circuit operating the drive for the track lifting unit so that the lifting stroke is terminated upon this contact which indicates the desired level of the track. The speed of the lifting unit drive is constant throughout the lifting stroke until the same is terminated. However, there is a certain lag between the time the sensor contacts the reference wire and the drive is stopped so that the track is usually raised above the desired level indicated by the reference wire, requiring additional track correction which is usually effectuated manually and is time-consuming. Furthermore, the sudden impact of the sensor on the wire upon contact therewith causes a lifting of the tensioned wire, which additionally distorts the track correction. Accuracy may be increased if the drive for the lifting unit moves very slowly so as to reduce inertia to a minimum. This, however, reduces the efficiency of teh machine below commercially acceptable limits.

It is accordingly the primary object of this invention to overcome the disadvantages indicated hereinabove and to provide a machine of the described type which works with the greatest accuracy at high speeds.

The above and other objects and advantages are accomplished in accordance with the invention when the sensor is constituted by a continuously adjustable electrical track level indicator having two indicator parts movable in respect to each other. One indicator part is in constant connection or engagement with the tensioned reference wire and the other indicator part is in connection with the track whereby the indicator indicates the track level prevailing at a track point whereto the other indicator part is connected and produces control signals corresponding thereto. A continuously adjustable control device for the track lifting unit drive is electrically connected to the indicator and receives the control signals, the control device being adjusted in response to the control signals and correspondingly actuating the drive for the track lifting unit.

In this manner, the indicator part which is in constant engagement with the reference wire at all times delivers an electrical control signal corresponding to the desired lifting stroke to the control device which determines the raising of the track to the desired track level. This enables the drive for the track lifting unit and its speed to be actuated proportionally to the extent of lifting, i.e. a certain lifting speed corresponds to each correction magnitude. If a considerable extent of track lifting is required to correct the track level, the lifting unit is first driven at high speed and, proportionally, as the error becomes smaller, the lifting speed is gradually reduced until this speed becomes zero as the track reaches the desired level. This practically eliminates excess raising of the track while maintaining a high working speed in obtaining a very accurate track leveling.

According to a preferred feature of the present invention, a setting control cooperates with the indicator to set the desired track level (zero adjustment), and a differentiating circuit unit is connected between the indicator with its setting control and the control device for the track lifting unit drive, an amplifier being advantageously connected between the differentiating circuit unit and the control device to amplify the control signal.

When the zero point set by the setting control of the indicator has been reached, which indicates that the track has been lifted to the desired level or grade, the control device will stop the lifting unit drive so that the track is no longer raised. However, certain track working conditions require a momentary change in the track level. For instance, it is customary to raise the track at rail joints a little higher than the remainder of the track, i.e. above the desired track level (zero point) set on the indicator, to provide a "bump" at the rail joints. This bump is gradually reduced by the train traffic passing thereover until the track level is even and smooth along its entire extension. This level is maintained much longer than if the track had originally been completely leveled, including the rail joint points, since the train loads depress the track at the rail joints and would thus cause depressions in the track level after a little while. To take care of this condition, it is necessary to be able to raise the track above the desired level at each rail joint and rapidly to reset the control to obtain the desired level at all other track points.

For this purpose, a preferred feature of this invention provides a setting control with a shaft carrying a pointer and a control disc carrying a scale. The disc is rotatable about the shaft into desired angular positions and is fixable in each such position. The pointer cooperates with the scale for setting the control temporarily to points deviating from the generally desired track level, i.e. a point on the scale other than zero, even during the lifting. Immediately after the deviation has been set, i.e. after the track has been raised at a rail joint above the desired level, the pointer may be re-set to zero so as to proceed with the correction to the desired level. The rotary adjustment of the scale in respect of the pointer into different fixable settings makes it possible readily to vary the settings from an original zero point to desired deviations therefrom.

While electromotor means may be used for driving the track lifting unit, the preferred drive for raising the unit is a hydraulic motor operated by a hydraulic circuit including a source of hydraulic fluid, a fluid supply line connecting the hydraulic fluid source to the motor and a constant-speed pump for the fluid in the supply line. In this case, the preferred control device is a solenoid servo valve having a coil electrically connected to the track level indicator and receiving the control signals therefrom to control the hydraulic fluid flow in response to the control signals.

Although such a hydraulic motor control has been proposed for track lifting, the control signals were optically derived in the conventional apparatus by means of a reference beam of electromagnetic radiation. In this known system, the sensor is a stop which gradually moves into the conical light bundle which constitutes the reference and a light receiver with a plurality of vertically spaced photocells receives varying portions of the light to control the servo valve. Such a control is complicated and, therefore, subject to operational difficulties and errors.

In contrast to this conventional control, the present invention provides a very simple and robust structure which continuously indicates the track level during the entire operation, rather than the stepwise control attained by the several photocells of the known optical control system, which continuous reading provides an absolutely continuous and gradual reduction in the lifting speed until the drive stops entirely when the desired track level has been reached. Furthermore, the reference wire use in the present control, instead of a beam of electromagnetic radiation, has the advantage that this reference may also be used for controlling other operations of the track tamping and leveling machine, such as the tamping pressure of the tamping tools and/or the lining of the track, which is impossible with a light beam.

In a preferred embodiment, two tensioned reference wires are provided, each associated with a respective track rail and each cooperating with a respective track level indicator. A measuring bogie is mounted for mobility on the track section to be leveled and means for adjustably supporting the forward ends of the tensioned wires is mounted on the measuring bogie. A control automatically adjusts the vertical positions of the forward wire ends in respect of each other. In such a reference systen, the desired superelevation of the track may be readily selected by providing a control comprising a rotary potentiometer mounted on the measuring bogie and a pendulum mounted on the rotary shaft of the potentiometer for pivotal movement in a vertical plane transverse to the track whereby the potentiometer indicates the superelevation of the track. A superelevation setting element for setting a desired superelevation at the potentiometer is connected to a differentiating circuit unit, and the means for vertically adjustably supporting the tensioned wire ends is electrically connected to the differentiating circuit unit for vertically adjusting a respective wire end.

In this arrangement, one wire end is vertically adjusted automatically in dependence on the difference between the actual superelevation indicated by the pendulum and the desired superelevation so that the two wires define a reference plane parallel to the desired track plane and in respect of which the track may be accurately corrected.

It will be advantageous to provide an independent drive, such as an electromotor, for vertically moving each forward wire end so that the control actuates one of the forward wire ends while a manually operable control switch is provided for actuating the other independent drive. In this manner, the control switch may be manually set for selecting the basic lifting stroke for the one rail while the superelevation is then automatically controlled by lifting the other rail in respect of the automatically controlled other wire end position.

For many operations, it will be desirable to have a visual indication for the track lifting operation by associating an indicating device, which may include a permanent recorder, with the differentiating circuit units in the lifting and superelevation controls.

It will also be useful if the rear ends of the tensioned wires in the leveled track section, the forward ends of the wires in the track section to be leveled, and the indicator part in connection with the track are supported on respective measuring bogies movable on the track and supported under the machine frame, the three measuring bogies being preferably so mounted that they may be temporarily lifted off the track. This saves the time-consuming preparation of the machine for operation, which has been required in known track leveling machines wherein the forward and rear measuring bogies are held spaced from the machine by rods and had to be pulled out to position them properly. In the present machine, the bogies are simply lifted off the track when not operational and are rapidly lowered into position under the machine frame when the machine is ready for operation.

A very advantageous structure is provided when the machine frame is of such elongation that the wire extends from end to end within the length of the frame, and at least one wire end is affixed directly to the machine frame. Particularly if a tension spring affixes the one wire end to the frame, this arrangement assures a taut tensioning of the wire and thus avoids wire vibrations or slack as much as possible to improve the accuracy of the reference.

The above and other objects, advantages and features of the present invention will become more apparent from the following detailed description of certain now preferred embodiments thereof, taken in conjunction with the accompanying drawing wherein

FIG. 1 is a schematic side elevational view of a track tamping and leveling machine incorporating the controls of this invention;

FIG. 1a is a control circuit diagram showing the control of the track lifting unit;

FIG. 2 is a schematic perspective view illustrating the reference system of the machine, with particular attention to the track superelevation control;

FIG. 2a is a control circuit diagram showing the superelevation control;

FIG. 3 shows a portion of the control circuit diagram of FIG. 1a with particular attention to the setting control; and

FIG. 4 is a cross sectional view of the setting control of FIG. 3.

Referring now to the drawing, wherein like reference numerals designate like parts functioning in an equivalent manner in all figures, FIG. 1 illustrates a track tamping and leveling machine with an elongated machine frame 3 mounted for mobility on the track 7 for moving in the direction of arrow A from a previously leveled track section, wherein the machine frame is supported on rear running gear 1, towards a track section to be leveled, wherein the machine frame is supported on front running gear 2. Mounted on the frame between the running gears are generally conventional vertically adjustable tamping tools 4 and a generally conventional track lifting unit 5. The tamping tool unit 4, which is illustrated as being of the general type shown in our U. S. Pat. No. 3,429,276, dated Feb. 25, 1969, is mounted immediately adjacent the rear running gear 1 so that the tamping tools may tamp the ballast underneath the ties and thus fix the track in the graded position after it has been raised to the desired track level by the track lifting unit 5 mounted forwardly of the tamping unit. The unit 5 is also conventional and includes a hydraulic drive motor 24 mounted on the frame 3 and having a vertically movable piston rod connected to a bracket supporting rail gripping rollers and glidably mounted on a vertical guide rail on the frame. As is also known, a track lining unit 6 is combined with the track lifting unit so that the track may be lined at the same time that it is graded. All of these structures are well known and may be substituted, of course, by other suitable tamping and track lifting means. Measuring bogies 8, 9 and 10 are vertically movably mounted on the machine frame and run on the track under the frame during operation of the machine while they may be lifted off the track when desired. The measuring bogies have respective vertical support rods 11, 12 and 13, the rear bogie 10 supporting the rear ends 18 of tensioned reference wires 14, 14 (see FIG. 2), the front bogie 8 supporting the front ends 15 of the wires, and the intermediate bogie 9 within the range of the tamping unit supporting the track level indicator 20. The ends of the track level reference wires 14, 14 are trained over guide rollers 16 and 19, respectively, which are mounted on support rods 11 and 13, respectively, the front ends being fixed to the rollers 16 while the rear ends are guided by rollers 19 to tension springs 17, 17 which affix the rear ends of the tensioned wires to frame 3 so that the wires are tautly held on the frame. Instead of tension springs 17, the rear ends of the wires could be attached to pressure fluid operated tensioning cylinders, with an equivalent result.

For the sake of clarity and since it forms no part of the present invention, the reference system for the lining unit 6 has been omitted from the drawing.

As best shown in FIG. 2, the track leveling reference system comprises two tensioned wires 14, 14 each associated with a respective track rail 7 and each cooperating with a respective track level indicator 20. The forward ends 16 of the wires are vertically adjustably supported on the rods 11 of measuring bogie 8 to control the superelevation of the track in a manner to be described hereinafter. First, however, the track leveling control of the present invention will be described with reference to FIGS. 1a, 3 and 4.

As shown in FIGS. 1 and 2, the support rods 12, 12 carry the two-part track level indicators which are shown as comprising one part consisting of a fork member 22 (see FIG. 1a) having two tines wherebetween the tensioned reference wire 14 is constantly held, and another part consisting of a rotary potentiometer 20 having a rotary shaft 21 whence the fork member 22 extends radially, the two indicator parts thus being movable in respect to each other. Each change in the vertical position of the track rail 7 in respect of the associated reference wire 14 automatically causes a movement of the radial fork member and a corresponding adjustment of the potentiometer, the changed resistance in the potentiometer producing a control signal corresponding and responsive to the change in the vertical track rail position. This control signal is used to operate a servo valve 23 in the manner illustrated in FIG. 1a.

As shown, the drive for raising the track lifting unit 5 is hydraulic motor 24 operated by a hydraulic circuit including a source of hydraulic fluid constituted by sump 32, a fluid supply line 32' connecting the hydraulic fluid sump to the motor 24, a fluid return line 33, and a constant-speed pump 31 for the fluid in the supply line 32'. The control device is solenoid servo valve 23 in the supply line. The coil 26 of the valve is electrically connected to the track level indicator by the control circuit illustrated in FIG. 1a.

In the illustrated control circuit, the potentiometer 20 is electrically connected to the solenoid valve coil 26 via a differentiating circuit unit 27 and a signal amplifier 25. The voltage changes automatically occurring in the potentiometer 20 during raising of the track are thus transmitted to the servo valve to change the hydraulic fluid supply to motor 24 correspondingly so that the motor speed is reduced proportionally to the rise of the track towards the desired track level until it stops entirely when this level has been reached. This control operates continuously rather than stepwise. The control would operate functionally identically if the hydraulic motor 24 were replaced by an electromotor, for instance, since it would reduce the electric power for the motor proportionally to the rise of the track with which the potentiometer 20 is connected and with which it rises.

While the electrical conductor from potentiometer 20 forms one input of the differentiating circuit unit 27, an electrical conductor from a setting control 28, also constituted by a rotary potentiometer, forms the other input of the differentiating circuit unit, the potentiometer 28 serving to set the zero point for the control, i.e. the point when the desired track level has been reached.

After the front end 15 of wire 14 in the track section to be leveled has been set, any voltage differences in differentiating circuit unit 27, which are due to differences in the vertical position of wire 14 and shaft 21 of indicator potentiometer 20, may be balanced or equalized by means of setting potentiometer 28 forming the second input of unit 27 so that the track lifting unit will always stop at the desired track level. This setting control will be further explained hereinbelow in connection with FIGS. 3 and 4. If desired, the potentiometer 28 may be manually operated to provide a manual control of servo valve 23.

The output of the differentiating circuit unit 27 is connected to signal amplifier 25 whose output feeds the amplified signal to servo valve coil 26 as well as to branch conductors leading to indicating devices 29 and 30. The indicating device 30 is a visually accessible meter whose scale shows the status of the lifting operation while indicating device 30 is a recorder wherein a stylus operated by the control signal permanently records the track level on a moving tape. If desired, meter 30 may be used for setting the potentiometer 28, i.e. the potentiometer pointer is moved until the pointer on meter 30 registers with zero on the scale of the meter.

The control circuit 34 for adjusting the vertical positions of the forward wire ends 16 in respect of each other is shown in FIG. 2a but it should be noted that the track lifting control according to the invention may be used also with a track level reference system comprising only a single tensioned reference wire running, for instance, centrally between the rails. However, when two wires each associated with a respective rail are used, as herein described, an automatic control can be provided not only for the track level but also for the superelevation of the track.

For this purpose, and as mentioned hereinabove, the front ends 16 of the two reference wires 14 are vertically adjustably mounted on support rods 11. For instance, the support rods may consist of two telescoping tubes, with the upper tubes carrying the guide rollers 15 to which the wire ends 16 are affixed. These upper tubes are vertically moved by respective electromotors 35a, 35b whose respective output shaft is coupled to the upper tube by a gear transmission. A transverse carrier beam 36 is affixed to the two supports rods 11, 11 and a rotary potentiometer 37 is mounted on the carrier beam to control the operation of the lift motors 35a, 35b. The rotary shaft 38 of control potentiometer 37 mounts a pendulum 39 for pivotal movement in a vertical plane tranverse to the track in the directions of the double-headed arrow shown in FIG. 2a. The rotary shaft 38 is freely rotatable by the swinging movement of the pendulum to indicate the actual superelevation of the track. A superelevation selecting element for setting the desired superelevation, which is embodied herein by another rotary potentiometer 40, provides one input for differentiating circuit unit 41 while the other input thereof is provided by potentiometer 37, both potentiometers being electrically connected to the unit 41 whose output provides a control signal to amplifier 42. The amplified control signal is fed to the electromotor lifting the wire end to be adjusted (in the illustrated embodiment motor 35a), the end of the wire associated with the grade rail having been previously set by manually operable switch 43 connected in the illustrated embodiment to the motor 35b by electrical conductor 43'. Of course, a switch (not shown) is provided to change the electrical connections to electromotors 35a, 35b when the grade rail is changed, i.e. when a change in the direction of the track curve occurs, so that electromotor 35a is connected to manual switch 43 and electromotor 35b is connected to control circuit 34.

Also, the amplified control signal in circuit 34 is fed by a branch conductor to indicating devices 44 and 45 which are identical to devices 29 and 30 so that they require no further description.

As illustrated in FIG. 2, it is also possible to associate further indicators 46 with each tensioned reference wire to produce additional control signals for other operations, such as the regulation of the tamping pressure or the lateral movement of the track, in which case operating motors for the tamping tools and/or the lateral track moving unit 6 are controlled by the additional control signals.

The operation of the machine will be apparent from the above description of its structure and will be summarized hereinbelow for a ready understanding of the invention.

First, one of the rails 7 is selected as the grade rail and the front end 15 of the tensioned reference wire 14 associated with the grade rail is vertically adjusted to the desired level by manual operation of switch 43. Secondly, the desired superelevation is selected by operating selecting potentiometer 40 which has digital indicators to show the selected parameters. When the machine operates in a straight track section, the potentiometer 40 will be set at zero, of course.

The differentiating circuit unit 41 receives its input from the potentiometer 40 set to indicate the desired superelevation and from potentiometer 37 which indicates the actual superelevation of the track. If unit 41 detects a voltage difference between these two inputs, it produces an output signal which operates lift motor 35a so as to raise the front end 15 of the reference wire 14 associated with the other rail to a level producing the desired superelevation. This automatic adjustment may be visually observed and recorded on instruments 45 and 44.

After the relative positions of the front ends of the reference wires have been thus adjusted, they define a reference plane in respect of which the track is to be leveled. As the machine advances in the direction of arrow A, the lifting of the track by unit 5 is continuously and automatically controlled in accordance with the zero setting of potentiometer 28, the speed of drive 24 for each track lifting unit 5 being controlled by servo valve 23 which, in turn, is adjusted in dependence on the angular position of indicator part 22 in respect of control potentiometer 20. The voltage received from potentiometer 20 will be at a maximum at the beginning of the lifting stroke so that the resultant control signal will fully open the servo valve to supply a maximum amount of hydraulic fluid to motor 24, thus operating it at maximum speed. As the track is raised towards the reference, the wire engaging the fork 22 will move the fork in respect of the potentiometer, thus increasing the resistance and decreasing the voltage. The resultant control signal will proportionally close the valve gradually to reduce the lifting speed of motor 24 until the valve will be entirely closed to stop the motor when the desired track level has been reached and without causing the track to be raised beyond this point.

As illustrated in FIGS. 3 and 4, the setting control 28 may be used to set deviations from the generally desired track level, for instance at rail joints where it is useful to raise the track initially above the grade of the remainder of the track. To enable such a temporary deviation from the desired track level determined by the reference system to be set, the setting potentiometer 28 comprises a rotary shaft 49 carrying a pointer 48 on a manually operably knurled knob 49a and a control disc 50 carrying a scale 47. The disc is rotatably journaled on potentiometer shaft 49 for rotary movement into desired angular positions and may be fixed by a set screw 51 in each such angular position, the pointer 48 cooperating with the scale 47 for setting the control.

The scale 47 may be calibrated in millimeters, for instance, FIG. 3 showing merely by way of example a lifting stroke deviation of .+-. 20 mm although a larger range up to 100 mm may be encompassed, if desired. Also, the minus range, i.e. a setting below the desired track level, may be reduced or eliminated in favor of a larger plus range on the scale. Of course, the respective resistance values of the potentiometer must correspong to the values marked on the scale so as to produce corresponding control signals.

Since, as explained hereinabove, the setting potentiometer 28 also serves for setting the zero point, i.e. for balancing the voltage in differentiating circuit unit 27 after the grade rail reference wire 14 has been set, it may occur that the pointer 48 does not register with the zero point on scale 47 when the potentiometer is set for the desired track level. This makes a setting for a deviation from the desired track level difficult because the operator must then add the required difference to the value with which the set pointer 48 has registered for the desired track level, and the pointer must then be turned to the calculated value. Furthermore, the operator must remember the original value so that the pointer can be turned back to it after the machine has passed the point of track level deviation. All this is avoided by the illustrated construction wherein the rotatable disc 50, which carries the scale, can be rotated into temporarily fixed different angular positions and rotated back into their normal position for normal operation.

Claims

We claim:

1. A track tamping and leveling machine comprising

1. a machine frame mounted for mobility on the track for moving from a previously leveled track section towards a track section to be leveled,

2. vertically adjustable track tamping tools mounted on the machine frame,

3. a track lifting unit mounted on the machine frame,

4. a drive for raising the track lifting unit,

5. a reference system in respect of which the track is leveled, the reference system including

a. a tensioned reference wire extending from the leveled track section to the track section to be leveled,

6. a continuously adjustable electrical track level indicator having

a. two indicator parts movable in respect to each other, one of the indicator parts being in constant connection with the tensioned reference wire and the other indicator part being in connection with the track whereby the indicator indicates the track level prevailing at a track point whereto the other indicator part is connected and produces control signals corresponding to the indicated track level, and

7. a continuously adjustable control device for adjusting the speed of the track lifting unit drive electrically connected to the indicator and receiving the control signals, the control device being adjusted in proportion to the control signals and correspondingly controlling the speed of the drive for the track lifting unit in proportion to the indicated track level.

2. The track tamping and leveling machine of claim 1, further comprising a signal amplifier connected between the indicator and the control device.

3. The track tamping and leveling machine of claim 1, further comprising a setting control on the indicator for setting the desired track level, and a differentiating circuit unit connected between the indicator with its setting control and the control device.

4. The track tamping and leveling machine of claim 3, whrein the setting control is a potentiometer.

5. The track tamping and leveling machine of claim 1, wherein the drive for raising the track lifting unit is a hydraulic motor operated by a hydraulic circuit including a source of hydraulic fluid, a fluid supply line connecting the hydraulic fluid source to the motor and a constant-speed pump for the fluid in the supply line, and the control device is a solenoid servo valve having a coil electrically connected to the track level indicator.

6. The track tamping and leveling machine of claim 1, wherein the one indicator part is a fork member having two tines wherebetween the tensioned reference wire is constantly held, and the other indicator part comprises a rotary potentiometer having a rotary shaft, the fork extending radially from the potentiometer shaft, and a measuring bogie mounted for mobility on the track and supporting the rotary potentiometer.

7. The track tamping and leveling machine of claim 1, wherein the tensioned wire has a rear end in the leveled track section and a forward end in the track section to be leveled, and further comprising three measuring bogies movable on the track and supported under the machine frame for respectively supporting the rear and forward ends of the wire and the other indicator part.

8. The track tamping and leveling machine of claim 1, wherein the tensioned reference wire has a rear end in the leveled track section and a forward end in the track section to be leveled, the machine frame being of such elongation that the wire extends from end to end within the length of the frame, and at least one of the wire ends being affixed directly to the machine frame.

9. A track tamping and leveling machine comprising

1. a machine frame mounted for mobility on the track for moving from a previously leveled track section towards a track section to be leveled,

2. vertically adjustable track tamping tools mounted on the machine frame,

3. a track lifting unit mounted on the machine frame,

4. a drive for raising the track lifting unit,

5. a reference system in respect of which the track is leveled, the reference system including

a. two tensioned reference wires each extending from the leveled track section to the track section to be leveled and associated with a respective one of the track rails,

6. a measuring bogie mounted for mobility on the track section to be leveled,

7. means for vertically adjustably supporting the forward ends of the tensioned wires on the measuring bogie,

8. a control for adjusting the vertical positions of the forward wire ends in respect of each other,

9. two continuously adjustable electrical track level indicators each cooperating with a respective one of the tensioned reference wires and each indicator having

a. two indicator parts movable in respect to each other, one of the indicator parts being in constant connection with the tensioned reference wire and the other indicator part being in connection with the track whereby the indicator indicates the track level prevailing at a track point whereto the other indicator part is connected and produces control signals corresponding thereto, and

10. a continuously adjustable control device for the track lifting unit drive electrically connected to the indicator and receiving the control signals, the control device being adjusted in response to the control signals and correspondingly actuating the drive for the track lifting unit.

10. The track tamping and leveling machine of claim 9, wherein the control comprises a rotary potentiometer mounted on the measuring bogie, the potentiometer having a rotary shaft, a pendulum mounted on the rotary shaft for pivotal movement in a vertical plane transverse to the track whereby the potentiometer indicates the superelevation of the track, a superelevation selecting element for setting a desired superelevation, and a differentiating circuit unit electrically connected to the rotary potentiometer and the superelevation selecting element, the means for vertically adjustably supporting the tensioned wire ends being electrically connected to the differentiating circuit unit for vertically adjusting a respective one of the wire ends.

11. The track tamping and leveling machine of claim 10, wherein the superelevation selecting element is a potentiometer.

12. The track tamping and leveling machine of claim 10, further comprising an amplifier electrically connected between the differentiating circuit unit and the vertical adjusting means.

13. The track tamping and leveling machine of claim 12, wherein the vertical adjusting means is an electromotor.

14. The track tamping and leveling machine of claim 10, further comprising an indicating device associated with the differentiating circuit unit.

15. The track tamping and leveling machine of claim 14, wherein the indicating device comprises a recorder.

16. The track tamping and leveling machine of 9, wherein the means for vertically adjustably supporting the wire ends comprises an independent drive for vertically moving each wire end, the control actuating one of the independent drives, and further comprising a manually operable control switch for actuating the other independent drive.

17. A track tamping and leveling machine comprising

1. a machine frame mounted for mobility on the track for moving from a previously leveled track section towards a track section to be leveled,

2. vertically adjustable track tamping tools mounted on the machine frame,

3. a track lifting unit mounted on the machine frame,

4. a drive for raising the track lifting unit,

5. a reference system in respect of which the track is leveled the reference system including

a. a tensioned reference wire extending from the leveled track section to the track section to be leveled,

6. a continuously adjustable electrical track level indicator having

a. two indicator parts movable in respect to each other, one of the indicator parts being in constant connection with the tensioned reference wire and the other indicator part being in connection with the track whereby the indicator indicates the track level prevailing at a track point whereto the other indicator part is connected and produces control signals corresponding thereto,

7. a setting control on the indicator for setting the desired track level, the setting control comprising a shaft carrying a pointer and a control disc carrying a scale, the disc being rotatable about the shaft into desired angular positions and being fixable in each of said positions, and the pointer cooperating with the scale for setting the control,

8. a continuously adjustable control device for the track lifting unit drive electrically connected to the indicator and receiving the control signals, the control device being adjusted in response to the control signals and correspondingly actuating the drive for the track lifting unit, and

9. a differentiating circuit unit connected between the indicator with its setting control and the control device.

18. A track tamping and leveling machine comprising

1. a machine frame mounted for mobility on the track for moving from a previously leveled track section towards a track section to be leveled,

2. vertically adjustable track tamping tools mounted on the machine frame,

3. a track lifting unit mounted on the machine frame,

4. a drive for raising the track lifting unit,

5. a reference system in respect of which the track is leveled, the reference system including

a. a tensioned reference wire extending from a rear end in the leveled track section to a forward end in the track section to be leveled,

b. the machine frame being of such elongation that the wire extends from end to end within the length of the frame, and

c. at least one of the wire ends being affixed directly to the machine frame,

6. a tension spring affixing the one wire end to the machine frame,

7. a continuously adjustable electrical track level indicator having

a. two indicator parts movable in respect to each other, one of the indicator parts being in constant connection with the tensioned reference wire and the other indicator part being in connection with the track whereby the indicator indicates the track level prevailing at a track point whereto the other indicator part is connected and produces control signals corresponding thereto,

8. a continuously adjustable control device for the track lifting unit drive electrically connected to the indicator and receiving the control signals, the control device being adjusted in response to the control signals and correspondingly actuating the drive for the track lifting unit.

19. A track tamping and leveling machine comprising

1. a machine frame mounted for mobility on the track for moving from a previously leveled track section towards a track section to be leveled,

2. vertically adjustable track tamping tools mounted on the machine frame,

3. a track lifting unit mounted on the machine frame,

4. a drive for raising the track lifting unit,

5. a reference system in respect of which the track is leveled, the reference system including

a. a tensioned reference wire extending from the leveled track section to the track section to be leveled,

6. a continuously adjustable electrical track level indicator having

a. two indicator parts movable in respect to each other, one of the indicator parts being in constant connection with the tensioned reference wire and the other indicator part being in connection with the track whereby the indicator indicates the track level prevailing at a track point whereto the other indicator part is connected and produces control signals corresponding thereto,

7. a setting control on the indicator for setting the desired track level,

8. a continuously adjustable control device for the track lifting unit drive electrically connected to the indicator and receiving the control signals, the control device being adjusted in response to the control signals and correspondingly actuating the drive for the track lifting unit,

9. a differentiating circuit unit connected between the indicator with its setting control and the control device, and

10. an indicating device associated with the differentiating circuit unit.

20. The track tamping and leveling machine of claim 19, wherein the indicating device comprises a recorder.