JPH02651B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention provides a front reference part that moves together with a track straightening machine that can run on the rails of a track, and that is interconnected.
This invention relates to a vertical curve correction device for a track straightening machine, which has a detection part and a rear reference part, and can automatically correct the entrance and exit parts of a vertical curve of a track by correcting the height of the front reference part. It is something.

[Prior Art] Generally, at a point where the slope of a track changes, if the slope bends into a convex shape, there is a risk of the train derailing due to the floating of the vehicle, and if it bends into a concave shape, the vertical The rapid change in directional momentum causes a large impact on the vehicle and the track, which may result in destruction of the vehicle and track. Moreover, in either case, the train becomes very shaken, making the ride uncomfortable for passengers. Therefore, in order to alleviate these negative effects, convex or concave arc-shaped curves are inserted at locations where the slope of the track changes in order to allow trains to pass safely and smoothly. This inserted arc-shaped curve is called a vertical curve, and a circular curve with a radius of 3000 m or more is usually used.

Therefore, as shown in Fig. 1, it moves on the rail R together with the track straightening machine while maintaining a constant distance from each other, and consists of a front reference part A, a detection part C, and a rear reference part B. Vertical curves are corrected using a conventional track straightening machine equipped with an elevation measuring device that uses a detection part C to detect deviations in the height of the track with respect to a reference line set above the rail passing through A and rear reference part B. When performing continuous work at the entrance and exit of a vertical curve, the type of vertical curve (hereinafter referred to as a concave curve if the vertical curve is upwardly concave or similar to this, and a concave curve if upwardly convex or similar to this) The correction work was carried out as follows, taking into consideration the vertical curve radius, vertical curve length, and the distance between the front reference part A, the detection part C, and the rear reference part B. .

When modifying the entrance of a vertical curve when the vertical curve is a concave curve.

(B) As shown in Figure 2a, the front reference part A enters the vertical curve Vo from the straight part S, and the detection part C remains within the vertical curve Vo of the front reference part A until it reaches the vertical curve entrance E. The correction amount Ya for the front reference part A or the correction amount Y'a for the detection part C is determined step by step by calculation or chart from the travel distance from the vertical curve entrance E and the radius of the vertical curve, and
The correction work is performed by lowering the detection unit C by the correction amount Ya or by increasing the detection unit C by the correction amount Y'a.

(b) As shown in Figure 2b, both the front reference part A and the detection part C enter the vertical curve Vo, and the vertical curve of the front reference part A until the rear reference part B reaches the vertical curve entrance E. The amount of correction to the front reference part A based on the traveling distance from the vertical curve entrance E in Vo, the distance between the front reference part A and the detection part C, and the vertical curve radius.
The correction amount Y'b for Yb or the detection part C is determined step by step by calculation or diagram, and the correction work is performed by lowering the previous reference part A by the correction amount Yb or raising the detection part C by the correction amount Y'b.

When modifying the entrance of a vertical curve when the vertical curve is a concave curve.

(B) As shown in Figure 3a, the front reference part A leaves the vertical curve Vo and enters the straight part S, and until the detection part C reaches the vertical curve exit O, the front reference part A's straight part S Based on the travel distance from the exit O of the vertical curve above, the distance between the front reference part A and the detection part C, and the vertical curve radius, the correction amount Yc for the front reference part A or the correction amount Y'c for the detection part C is determined in stages. Calculate or use a chart to determine the amount of correction for the front standard part A.
The correction work is performed by lowering the detection part C by the correction amount Y'c or by increasing the detection part C by the correction amount Y'c.

(b) As shown in Figure 3b, both the front reference part A and the detection part C enter the straight part S, and until the rear reference part B reaches the vertical curve exit O, the straight part S of the front reference part A is Travel distance from the vertical curve exit O above,
From the interval length between the front reference part A and the detection part C, the interval length between the front reference part A and the rear reference part B, and the vertical curve radius, the correction amount Yd for the front reference part A or the correction amount Y'd for the detection part C is calculated. is calculated or charted step by step, and the correction work is performed by lowering the front reference part A by the correction amount Yd or by lowering the detection part C by the correction amount Y'd.

When modifying the entrance of a vertical curve when the vertical curve is a convex curve.

(B) As shown in Fig. 4a, the front reference part A enters the vertical curve V _T from the straight part S, and until the detection part C reaches the entrance E of the vertical curve, the front reference part A and the detection part C The amount of correction for is the same as in case (a) above, and is Ya and Y'a, respectively, but the direction of correction is different, and the front reference part A is raised by the correction amount Ya, or the detection part C is raised by the correction amount Y' Perform correction work by lowering only a.

(b) As shown in Figure 4b, both the front reference part A and the detection part C enter the vertical curve V _T , and until the rear reference part B reaches the entrance E of the vertical curve, the front reference part A and the detection part The amount of correction for part C is as described in (b) above.
Same as in the case of , Yb and Y'b are respectively, but the correction direction is different, and the front reference part A is the correction amount.
The correction work is performed by increasing the amount by Yb or decreasing by the correction amount Y'b.

When modifying the vertical curve exit part when the vertical curve is a convex curve.

(B) As shown in Figure 5a, when the front reference part A leaves the vertical curve V _T and enters the straight part S, the front reference part A and the detection part The amount of correction for C is the same as in (a) above, and is Yc and Y′c, respectively, but the correction direction is different. Lower it and do the correction work.

(b) As shown in Figure 5b, both the front reference part A and the detection part C enter the straight part S, and until the rear reference part B reaches the vertical curve exit O, the front reference part A and the detection part C The amount of correction for is the same as in case (b) above, and is Yd and Y′d, respectively.
The correction direction is different, and the correction work is performed by raising the front reference part A by Yd or lowering the detection part C by Y'd.

[Problems to be Solved by the Invention] As described above, in the vertical curve correction work using the conventional track straightening machine, as in the cases of (a) and (b) above, the type of vertical curve, Each time the working conditions at the entrance and exit of a vertical curve change, the work is stopped one by one, and corrections corresponding to the working conditions are made at the front reference section A or at the detection section C. It was necessary to determine the correction amount step by step by calculation or diagram, set the obtained correction amount in the front reference part A or the detection part C, and continue the correction work. Therefore, vertical curve correction work not only requires a great deal of effort and time, but also requires great skill, has low work efficiency, and has the drawbacks of uneven track finishing and low finishing accuracy. .

[Means for Solving the Problems] The present invention has been made to eliminate the above-mentioned drawbacks. In a vertical curve correction device having a front reference part, a detection part, and a rear reference part, a travel distance detector outputs a signal proportional to the travel distance of the track straightening machine, and an output of the travel distance detector is inputted, A travel distance setting device that always outputs a predetermined signal when the track straightening machine travels a distance equal to the distance between the reference parts between the front reference part and the rear reference part, and the output of this travel distance setting device are input. a plurality of function generating circuits that output a value obtained by multiplying the distance traveled by the front reference part by a correction function while the front reference part travels within the vertical curve from the entrance or exit of the vertical curve for a distance equal to the distance between the reference parts. a vertical curve correction function generator, a correction method switching device that selects a function generation circuit of the vertical curve correction function generator to set a desired vertical curve correction method; A vertical curve radius setting device that inputs the output from the curve correction function generator, divides it into a ratio corresponding to the vertical curve radius as a correction amount for the traveling distance of the front reference part, and outputs it, and a vertical curve a front reference part correction device having an elevation correction amount setter for setting the amount of depression correction given to the front reference part; a correction amount detector for detecting the correction amount for the height of the front reference part; a servo amplifier that inputs the output of the height correction amount setter and the output of the correction amount detector of the front reference portion correction device and outputs a correction control signal to the front reference portion correction device; and the output of the travel distance detector. and a correction completion detector which compares the output of the reference section interval setter and the reference part interval setter, and outputs a correction completion signal when the two match, and cuts off the signal from the mileage detector. It is an object of the present invention to provide a vertical curve correction device for a track straightening machine having the following characteristics.

[Function] When correcting the vertical curve of the track with the vertical curve correction device of the track straightening machine configured as described above, set a predetermined value in each setting device, and then start the track straightening machine. First, the front reference part enters the vertical curve from the entrance of the vertical curve or enters the straight part from the exit of the vertical curve, then the detection part enters the vertical curve from the entrance of the vertical curve or enters the straight part from the exit of the vertical curve, and finally When the rear reference section reaches the vertical curve entrance or vertical curve exit, that is, when the front reference section has traveled the set reference interval length from the vertical curve entrance or vertical curve exit, the modification completion detector indicates that the modification is complete. A signal is output, which disengages the clutch from the travel distance detector and completes the vertical curve correction operation at the entrance or exit of the vertical curve. During that time, the front reference part is processed through the servo amplifier, the front reference part correction device, and the correction mechanism according to the set correction method, set vertical curve radius, and drop correction amount according to the traveling distance of the front reference part. The height of the vertical curve is corrected, the height deviation of the vertical curve with respect to the corrected reference line passing through the front reference part and the rear reference part is detected by the detection unit, and the detected deviation of the vertical curve is detected by the track correction machine. Corrected by In this way, the correction work for the entrance or exit part of a vertical curve, which was conventionally done in stages and required skill and a great deal of effort and time, can now be done continuously without requiring skill and a great deal of effort and time. , can be performed with high precision and high efficiency.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 6 is a block diagram of an embodiment of the vertical curve correction device for a track straightening machine according to the present invention, and FIG. 7 is an output voltage characteristic diagram of each function generating circuit of the vertical curve correction function generator.

In FIG. 6, the main parts of the vertical curve correction device of the present invention are a traveling distance detector 1, a traveling distance setting device 2,
Vertical curve correction function generator 3, correction method switching device 4,
It is comprised of a vertical curve radius setter 5, a height correction amount setter 6, a correction amplifier 7, a front reference section correction device 11, a reference section interval setter 9, and a correction completion detector 10.

The traveling distance detector 1 is configured to output the rotational speed of the wheels 13 of the track straightening machine to a potentiometer via the clutch 12, and to obtain a voltage proportional to the traveling distance of the track straightening machine. There is. This voltage is then amplified by the amplifier 14, and its output is input to the mileage setting device 2.

The mileage setter 2 inputs the output of the mileage detector 1 amplified by the amplifier 14, and calculates the mileage using a dial (not shown) as the distance between the front reference section A and the rear reference section B (hereinafter referred to as the reference section). When the track straightening machine travels a distance equal to the reference part interval length (abbreviated as interval length), it is configured to always output a constant voltage, for example, 10V.

Therefore, the distance traveled by the front reference part A within the vertical curve from the entrance E of the vertical curve is the travel distance of the track straightening machine, so assuming the maximum output voltage is 10V, it is proportional to the travel distance of the front reference part A. The resulting voltage is output to the vertical curve correction function generator 3.

Further, the vertical curve correction function generator 3 is composed of a plurality of function generation circuits 3a, 3b, 3c, and 3d. In other words, in FIG. 6, the function generating circuit 3a corresponds to FIGS. The function generating circuit 3b outputs a voltage obtained by multiplying the output voltage of the mileage setting device 2 by the correction function for the mileage of the front reference part A while traveling by the distance between the reference parts. Corresponding to b, when the vertical curve is a concave curve, the travel distance of the front reference part A while the front reference part A travels on the straight part from the vertical curve exit O by the distance between the reference parts. A voltage obtained by multiplying a correction function for the distance setting device 2 by the output voltage of the mileage setting device 2 is outputted, and the shapes of these correction functions are shown by solid lines in FIG. Further, the function generating circuit 3c has a fourth function generating circuit 3c.
In the case where the vertical curve is a convex curve and corresponds to Figures a and b, the front reference part A travels within the vertical curve from the vertical curve entrance E by the distance between the reference parts. It outputs a voltage obtained by multiplying the correction function for the traveling distance by the output voltage of the traveling distance setting device 2, and the function generating circuit 3d corresponds to Fig. 5 a and b, and when the vertical curve is a convex curve. At the exit of the vertical curve, the output voltage of the travel distance setting device 2 is multiplied by the correction function for the travel distance of the front reference part A while the front reference part A travels on the straight part from the vertical curve exit O by the distance between the reference parts. The shapes of these correction functions are shown by dotted lines in FIG. In FIG. 7, the horizontal axis represents the output voltage of the mileage setting device, the vertical axis represents the input voltage of the vertical curve correction function generator 3, and the vertical axis represents each function generating circuit 3a, 3b, 3c, 3d.
The output voltage is set.

The correction method switching device 4 includes selection switches 4a and 4b.
The selection switch 4a is an interlocking switch that can simultaneously connect or disconnect the function generation circuits 3a and 3b or the function generation circuits 3c and 3d. Therefore, the function generation circuits 3a, 3b, 3b of the vertical curve correction function generator 3 are selected by the selection switches 4a, 4b.
By appropriately selecting 3c and 3d, the vertical curve correction method can be set. That is, the selection switch 4a is connected to the function generation circuits 3a and 3b,
If the selection switch 4b is connected to the function generation circuit 3a side, it becomes a correction method for the vertical curve entrance when the vertical curve is a concave curve, and the selection switch 4b is connected to the function generation circuit 3a side.
If it is connected to the b side, it becomes a correction method for the vertical curve exit section when the vertical curve is a concave curve. Also select switch 4
If a is connected to the function generation circuits 3c and 3d, and the selection switch 4b is connected to the function generation circuit 3c side, it becomes a correction method for the vertical curve entrance when the vertical curve is a convex curve, and the selection switch 4b is connected to the function generation circuit 3c. If it is connected to the 3d side, it becomes a correction method for the exit section when the vertical curve is a convex curve.

Note that the function generation circuits of the vertical curve correction function generator 3 are not limited to the above four types, and can be increased or decreased as desired. For example, as is clear from FIG. 7, the correction functions for the entrance and exit portions of vertical curves simply have different signs depending on whether the vertical curve is a concave curve or a convex curve. Only function generating circuits for either concave or convex curves can be used. Further, when a transition curve is added to the vertical curve, a function generating circuit for a correction function for the transition curve must be added.

The vertical curve radius setting device 5 sets the vertical curve radius, and converts the voltage output from the vertical curve correction function generator 3 via the correction method switching device 4 to the front reference section A.
The voltage divided into the ratio corresponding to the radius of the vertical curve is output as a correction amount for the traveling distance.

The height correction amount setter 6 sets the drop correction amount required according to the line condition (the amount to correct the drop based on experience according to the line condition), converts it into voltage, and outputs it. It is.

The servo amplifier 7 includes an amplifier 15 that adds the output voltage of the vertical curve radius setter 5 and the output voltage of the height correction amount setter 6, and a correction amount detector 8 of the front reference portion correction device 11 and the output voltage of this amplifier 15. An amplifier circuit 17 amplifies the output voltage of the amplifier 16 and outputs a correction signal to the pre-reference section correction device 11.

The front reference portion correction device 11 includes a servo motor 18,
The speedometer generator 19 is composed of a speedometer generator 19 directly connected to the servo motor 18, a correction mechanism 20, and a correction amount detector 8 that detects the correction amount of the correction mechanism 20 and converts it into voltage. The output voltage is fed back to the amplifier circuit 17 of the servo amplifier 7, and automatic control is performed so that the servo motor 18 rotates at a stable speed.

The correction completion detector 10 includes an amplifier 21 that compares and calculates the output voltage of the mileage detector 1 amplified by the amplifier 14 and the output voltage of the reference section interval setter 9 that sets the reference section interval and converts it into a voltage. , waveform shaping circuit 2 for increasing the operation accuracy of the relay 23
2 and a relay 23, and when the output voltage of the mileage detector 1 via the amplifier 14 and the output voltage of the reference interval setting device 9 match, the relay 23 is operated via the waveform shaping circuit 22, clutch 1
2, the connection between the wheels 13 and the travel distance detector 1 is disconnected, and the completion of the vertical curve correction work using one correction method is detected. Note that the amplifier 21
The relay 23 may be activated by the signal, and the normally open contact 23a of the relay 23 may be closed to cut off the input to the amplifier circuit 17 of the servo amplifier 7.

Since the vertical curve correction device of the present invention has the above-described configuration, its operation will be explained next.

When the front reference part A connected to the track straightening machine reaches the entrance E or the exit O of the vertical curve, the track straightening machine is temporarily stopped, and the travel distance setting device 2 indicates that, for example, the track straightening machine is the reference part. Maximum output voltage when traveling the interval length
Set to output 10V, set the reference part interval length in the reference part interval setter 9, and select the selection switch 4a, 4 of the correction method switching device 4 according to the type of vertical curve.
Select the correction method using b. For example, in FIG. 6, the selection switch 4a is the function generating circuit 3.
Since the selection switch 4b is connected to the function generation circuit 3a side, the correction method in this case is to correct the entrance portion when the vertical curve is a concave curve.

The correction method set in FIG. 6 will be mainly explained below.

Next, the vertical curve radius is set in the vertical curve radius setting device 5, and if necessary, the depression correction amount is set in the height correction amount setting device 6.

After that, when the clutch 12 is engaged with the travel distance detector 1 and the track straightening machine is started, the front reference part A passes through the vertical curve entrance E and enters the vertical curve, and then the detection When the section C enters the vertical curve and the rear reference section B finally reaches the vertical curve entrance E, the correction work for the vertical curve entrance is completed. During this time, the mileage detector 1 outputs a voltage proportional to the mileage, and this output is applied to the front reference portion A, that is, the track alignment, by the distance setter 2. The voltage is divided so that it always has a constant maximum voltage, for example 10V, when the main machine is running, and is output to the vertical curve correction function generator 3. Vertical curve correction function generator 3
From there, the mileage setting device 2 changes the correction function corresponding to the function generation circuit set by the correction method switching device 4.
A voltage multiplied by the output voltage of is outputted and inputted to the vertical curve radius setting device 5. The vertical curve radius setter 5 divides this voltage into a ratio corresponding to the vertical curve radius and outputs the voltage to the servo amplifier 7 as a correction amount for the traveling distance of the front reference section A. On the other hand, the drop correction amount set in the height correction amount setter 6 is also converted into a voltage and output to the servo amplifier 7. The output voltages of the vertical curve radius setter 5 and the height correction amount setter 6, which are input to the servo amplifier 7, are compared and calculated by the amplifier 15. The calculation result indicates a voltage obtained by adding the correction amount of the elevation correction amount setter 6 to the correction amount of the front reference part A for the traveling distance, and is fed back from the correction amount detector 8 of the front reference part correction device 11. A comparison operation is performed in the amplifier 16 with the voltage corresponding to the amount of correction of the previous reference section, and the difference voltage is calculated in the amplifier circuit 17.
is amplified and output to the control winding of the servo motor 18 of the front reference section correction device 11.
8 and drives the correction mechanism 20 via the speedometer generator 19 to correct the height of the front reference portion A according to the set correction method. In this case, the output voltage of the speedometer generator 19 is fed back to the amplifier circuit 17 to rotate the servo motor 18 at a stable speed, and the correction mechanism 20 corrects the height of the front reference part A with high accuracy. The correction amount is detected by the correction amount detector 8 and fed back to the amplifier 16 of the servo amplifier 7. When the correction amount of the correction mechanism 20 is a predetermined correction amount, the output voltage of the amplifier 15 and the correction amount detector input the output voltage of the vertical curve radius setting device 5 and the output voltage of the height correction amount setting device 6. 8 have the same value, the differential voltage between the outputs of the amplifier 16 becomes zero, and therefore the output voltage of the amplifier circuit 17 also becomes zero, and the servo motor 18 is not driven. In this way, when the front reference part A travels from the vertical curve entrance E by the reference part interval length and completes the correction work, the output voltage of the amplifier 14 and the output voltage of the reference part interval setter 9 become equal, and the correction work is completed. A correction completion signal is sent from the amplifier 21 of the completion detector 10 to the relay 23 via the waveform shaping circuit 22, and the relay 23 is activated to release the clutch 12 and correct the vertical curve entrance when the vertical curve is a concave curve. Complete the vertical curve correction work. At this time, the rear reference part B has just reached the vertical curve entrance E, and the subsequent correction work inside the vertical curve will be performed in the same state as when the rear reference part B reached the vertical curve entrance E. The process continues until the reference portion A reaches the vertical curve exit portion O. When the front reference part A reaches the vertical curve exit O, the selection switch 4b of the correction method switching device 4 is connected to the function generation circuit 3b side of the vertical curve correction function generator 3, and the setting of the correction method is changed until the vertical curve is concave. In a curve, instead of the vertical curve exit part, in the same way as described above, the correction work within the vertical curve is performed until the rear reference part B reaches the vertical curve exit O, and from then on, the rear reference part B is the vertical curve exit part. It is sufficient to proceed to the correction work on the straight portion while maintaining the correction state when O is reached.

During this time, the height deviation of the track including the entrance and exit parts of the vertical curve with respect to the reference line above the rail passing through the rear reference part B and the corrected front reference part A is continuously measured by the detection part C. This measured height deviation of the track is corrected by a track correction machine.

If the vertical curve is a convex curve, the correction method switching device 4
The selection switch 4a is connected to the function generation circuits 3c and 3d of the vertical curve correction function generator 3, and when the vertical curve entrance part is to be corrected, the selection switch 4b is connected to the function generation circuit 3c side, and the selection switch 4b is connected to the function generation circuit 3c side when the vertical curve entrance part is to be corrected. In the case of correction work, the selection switch 4b may be connected to the function generation circuit 3d side and the correction work may be performed in the same manner as described above.

[Effect of the invention] As is clear from the above description, if the vertical curve correction device of the track straightening machine of the present invention is used, the reference part interval length, vertical curve radius, and drop correction amount can be set, and the vertical Track alignment can be performed by simply setting the correction method by selecting the function generation circuit of the vertical curve correction function generator using the selection switch of the correction method switching device, taking into account the type of curve and whether it is at the entrance or exit of a vertical curve. Necessary signals are sequentially inputted to the vertical curve correction device of the machine, and the difficult correction work of the vertical curve entrance and exit can be performed automatically. Therefore, the huge amount of labor and time that conventionally required step-by-step work is no longer required, no skill is required, there is no variation in finish, and vertical curve correction work can be performed with high precision and high efficiency. be able to.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing the configuration of the rail height inspection device, Fig. 2 a, b is a schematic diagram showing a method for correcting the entrance of a vertical curve when the vertical curve is a concave curve, Fig. 3 a,
Fig. 4b is a schematic diagram showing a method of correcting the exit portion of a vertical curve when the vertical curve is a concave curve; Fig. 4a and b are schematic diagrams showing a method of correcting the entrance portion of the vertical curve when the vertical curve is a convex curve; Figures 5a and 5b are schematic diagrams showing a method for correcting the exit portion of a vertical curve when the vertical curve is a convex curve, Figure 6 is a block diagram of an embodiment of the present invention, and Figure 7 is a diagram showing the generation of a vertical curve correction function. FIG. 4 is an output voltage characteristic diagram of each function generating circuit of the device. 1... Mileage detector, 2... Mileage setter, 3... Vertical curve correction function generator, 4... Correction method switching device, 5... Vertical curve radius setter, 6... Height correction amount setting. device, 7... Servo amplifier, 8... Correction amount detector, 9... Reference section interval setting device, 10...
Correction completion detector, 11... Front reference portion correction device, 1
4...Amplifier, 18...Servo motor, 19...
Speedometer generator, 20...correction mechanism.

Claims (1)

[Claims] 1. In a vertical curve correction device that moves together with a track straightening machine that can run on the rails of a track, and has a front reference part, a detection part, and a rear reference part connected to this track straightening machine, A travel distance detector outputs a signal proportional to the distance, and the output of this travel distance detector is input, and when the track straightening machine travels a distance equal to the distance between the reference parts between the front reference part and the rear reference part. A mileage setting device that always outputs a predetermined signal,
Input the output of this travel distance setting device and multiply it by the correction function for the travel distance of the front reference part while the front reference part travels within the vertical curve from the entrance or exit of the vertical curve for a distance equal to the distance between the reference parts. a vertical curve correction function generator having a plurality of function generation circuits for outputting values; and a correction method switching device for selecting a function generation circuit of the vertical curve correction function generator and setting a desired vertical curve correction method. The vertical curve correction function generator inputs the output from the vertical curve correction function generator through this correction method switching device, divides it into a ratio corresponding to the vertical curve radius as a correction amount for the traveling distance of the front reference part, and outputs the output. A front reference part correction device that has a curve radius setter, a height correction amount setter that sets the amount of depression correction given to the vertical curve as necessary, and a correction amount detector that detects the amount of correction of the height of the front reference part. and inputs the output of the vertical curve radius setter, the output of the height correction amount setter, and the output of the correction amount detector of the front reference portion correction device, and outputs a correction control signal to the front reference portion correction device. A servo amplifier that compares the output of the distance detector and the output of the reference interval setter, and when the two match, outputs a correction completion signal and immediately cuts off the signal from the distance detector. A vertical curve correction device for a track straightening machine, comprising a correction completion detector.