CA1140393A - Method and apparatus for correcting railroad track using a dynamic loading record of track condition - Google Patents
Method and apparatus for correcting railroad track using a dynamic loading record of track conditionInfo
- Publication number
- CA1140393A CA1140393A CA000337666A CA337666A CA1140393A CA 1140393 A CA1140393 A CA 1140393A CA 000337666 A CA000337666 A CA 000337666A CA 337666 A CA337666 A CA 337666A CA 1140393 A CA1140393 A CA 1140393A
- Authority
- CA
- Canada
- Prior art keywords
- track
- record
- geometric condition
- condition
- actual
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01B—PERMANENT WAY; PERMANENT-WAY TOOLS; MACHINES FOR MAKING RAILWAYS OF ALL KINDS
- E01B35/00—Applications of measuring apparatus or devices for track-building purposes
-
- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01B—PERMANENT WAY; PERMANENT-WAY TOOLS; MACHINES FOR MAKING RAILWAYS OF ALL KINDS
- E01B2203/00—Devices for working the railway-superstructure
- E01B2203/16—Guiding or measuring means, e.g. for alignment, canting, stepwise propagation
Landscapes
- Engineering & Computer Science (AREA)
- Architecture (AREA)
- Civil Engineering (AREA)
- Structural Engineering (AREA)
- Length Measuring Devices With Unspecified Measuring Means (AREA)
- Adjustment Of The Magnetic Head Position Track Following On Tapes (AREA)
- Machines For Laying And Maintaining Railways (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An improved technique for correcting errors in track, for example errors in alignment and cross-level. A record of the actual geometric condition of a section of track is obtained by running a recording car operating at a predetermined speed and axle loading over the track. A record which may be on magnetic tape is thus obtained for one or more parameters such as alignment. In some cases this record may be used directly to derive electrical error signals which control a track moving device which moves the track in a direction to remove the error. Where the parameter of interest is alignment and the section of track is curved, a desired geometric condition has to be obtained for comparison with the actual geometric condition to derive the electrical error signals. One way of obtaining the desired geometric condition is to process the record to achieve a running average taking over ten or so consecutive sample points.
An improved technique for correcting errors in track, for example errors in alignment and cross-level. A record of the actual geometric condition of a section of track is obtained by running a recording car operating at a predetermined speed and axle loading over the track. A record which may be on magnetic tape is thus obtained for one or more parameters such as alignment. In some cases this record may be used directly to derive electrical error signals which control a track moving device which moves the track in a direction to remove the error. Where the parameter of interest is alignment and the section of track is curved, a desired geometric condition has to be obtained for comparison with the actual geometric condition to derive the electrical error signals. One way of obtaining the desired geometric condition is to process the record to achieve a running average taking over ten or so consecutive sample points.
Description
This invention relates to a process for correcting railway tracks.
Such a technique is known in which a survey of a track is made and pen chart recorder makes a recording of the track representing the condition of the track before alignment. A skilled operator then takes the recording and draws a "best line" through the recorded curve to average out the errors. The corrected record is then used in a track aligning apparatus which makes use of a photocell/potentiometer/shadow board technique for aligning the surveyed track.
In another known technique an optical record is obtained during survey of the track and this can be compared with a "standard"
optical record, for example by simiimultaneous screening. Here again, a skilled operator is necessary to interpret the differences between the actual and the ideal curves.
Both of the above techniques have the disadvantage that the alignment information fed to the track aligning machine is not mathematically accurate but is dependent on the skill and experience of the operator.
Accordingly, it is an object of the present invention to provide a technique for correcting track which is not dependent on the skill of the operator.
Another object of the invention is to provide a method of correcting a track using a record of the actual geometric conditions of the track under dynamic loading conditions.
It is a further object of the invention to provide a techni(lue for correcting track errors in which an ideal or desired condition is compared with the actual record to derive appropriate error signals.
According to a broad aspect of the invention a method of ~14~93 correcting railroad track comprises passing a recording car along the track at a predetermined speed and axle loading related to the speed and axle loading experienced by the track when in normal operation to obtain a record on a recording medium representing the actual geometric condition of at least one parameter of a length of track under predetermined dynamic loading conditions, processing electronically the record to obtain a desired geometric condition, comparing the actual geometric condition with the desired geometric condition to derive error signals indicative of the difference between the actual geometric condition and the desired geometric condition and using the error signals in a track correction vehicle to control track moving means on the track correction vehicle in a direction to reduce the difference.
In the case of a straight section of track, the first record can be used to derive the error signals without any processing step but for curved sections of track where the alignment is the parameter under consideration the first record has to be processed to obtain a desired geometric condition or a desired geometric condition has to be obtained in some other way.
The desired geometric condition may be recorded on a recording medium to obtain a record of the desired geometric condition, this record then being compared with the first mentioned record.
Alternatively, the step of obtaining a second record may be omitted, the desired geometric condition being immediately compared with the record representing the actual values of the track condition.
One way of obtaining the desired geometric condition is to compute electronically a running average value using, say, ten readings from the actual record representing track. values at 2 meter intervals.
The invention will now be described in greater detail with reference to the accompanying drawings, in which:
Figure 1 is a block diagram illustrating schematically the general system of the present invention; and Figure 2 is a schematic diagram of the invention as applied to a section of track and illustrating an exemplary embodiment of central processing unit.
The components shown in Figure 1 may be divided into three categories, namely input 1, central processing unit 2 and outputs 3. The main input may be a digital magnetic tape 4 or an FM magnetic tape 5. In either case the tape has been derived previously in known manner from a known track recording car running over a particular section of track. Such a tape typically carries separate spaced tracks each carrying a record of a specific parameter indicative of the geometric condition of the track. Thus, the tape would have records of the alignment, left rail elevation right rail elevation, cross level etc.
Another input is obtained from a block 6 entitled distance synchronization which ensures that the information on the tape is processed in synchronism with the movement of a track correction vehicle which carries the apparatus of Figure l over the section of track to be corrected. The track correction vehicle carries in known manner hydraulic mechanisms for moving ~he ~rack to the left or right and for raising the left and right rails independently. The block 7 entitled track position sensors symbolises sensors which run on the rails and derive input signals corresponding to particular locations sensed on the track, for example crossings.
With reference to the central processing unit 2, a magnetic tape controller lO under the control of a microprocessor ll controls the running of the digital tape 4. The input from ~he distance synchronization is fed to the microprocessor ll which causes the magnetic tape controller lO to control the speed of the magnetic tape 4 according to the speed of the track correction vehicle so that the tape is unwinding in synchronism with the movement of the vehicle.
The digital information on the tape is read in the magnetic tape controller and passed to the microprocessor ll which has been pre-programmed to derive a digital output signal representative of the difference between the data read at a particular point on the tape and data indicative of an ideal or preferred track condition.
It should be understood that probab]y not all the recorded information on the tape would be read and, for the purpose oE the present explanation, we will consider that the information which is being read is the track alignment record and the cross-level record. A dlgital output signal for the difference between the actual and preferred track a~ignment condition would, therefore, be obtained and further cligital output signal for the difference between the actual and preferred cross-level condition would therefore, be obtained. These cligital output signals are fed to a digital/analog converter 12 to derive analog "error"
V3~'3~
signals for controlling the track corr0ction mechanisms on the track correction vehicle.
The analog/digital converter 13 also sho~n as forming part of the central processing unit 2 is used to convert the analog input from the track position sensors 7 to digital form for handling by the microprocessor. The analog/digital converter 13 is also capable of providing suitable digital input if the track record is provided in the form of FM magnetic tape 5 rather than digital magnetic tape.
The input from the track position sensors is processed in the microprocessor 11 which then alerts the track correction vehicle to stop at crossings, for example. The use of such track position sensors for this purpose is conventional and, accordingly, will not be described in any further detail.
The digital/analog converter 12 derives output signals correspond-ing to the deviation of the track from the preferred or ideal values in respect of the parameters of interest, in the present example alignment and cross-level. Thus a box 15 entitled alignment control symbolizes a servo-mechanism for driving the track alignment mechanism either right or left depending on the alignment error signal input from the digital analog converter. Two boxes 16 and 17 cntitled left surface control and right surface control symbolize servo-mechanisms for driving lifting mechanisms for the left and right rails, respectivoly. If the cross-level "error" signal indicates that the left rail should be higher, then a signal a~pears at the input of the left surface control 16 causing the left rail to be lifted a certain amount, and, similarly, for an error signal indicating that the right rail should be higher, a signal appears on the input of the right surface control 17.
-~140393 A visual comyarator 20 may also be provided in the outputs 3 to give the operator a visual indication of, for example, the actual track condition, the preferred track condition and/or the error condition.
The visual comparator could take the form of an oscilloscope to which signals rom the microprocessor 11 and the digital analog converter 12 are applied as inputs ~hus deriving on the oscilloscope screen, three traces corresponding, respectively, to the actual track condition as recorded on the magnetic tape, the preferred track condition as obtained in the microprocessor and the "error" condition as obtained from the output of the digital/analog converter. Obviously, if a track error record is made independently from the track correction vehicle for use therein, the actual track condition and the preferred track condition could be dispensed with an only the error record would be displayed. Obviously the track alignment condition and/or the cross-level condition or any other parameter could be displayed either simultaneously or as alternatives.
The last box 21 in the outputs symolizes failure alarms which would operate if there was a power failure or a failure in any portion of the central processing unit 2 such as the microprocessor 11 or digital/ analog converter 12. The alarms would also bc capable of signalling incorrect operation of the track position sensors 7.
The alarms 21 would be arranged in known manner, on a console for monitoring by the operator.
Turnin~ now to Figure 2, an example of how the microprocessor may be programmed to obtain a preferred track condition is illustrated.
A portion 25 of a track which is to be corrected in alignment and cross-level is shown. The distance synchronization 6 is shown connected to a vehicle wheel 26 running on the track and may be in the form of a tachogenerator deriving a voltage dependent on the speed of the track correction vehicle. In that case, the output of the distance synchronisation 6 is fed to a voltage divider 27 which derives an output voltage the magnitude of whicll is dependent on the voltage from the distance syncl1ronization 6. The output voltage with appropriate amplification ~no~ shown) is used to control the tape drive 28 which forms part of the magnetic tape controller 10 and which drives the magnetic tape 29 by means of sprockets 30 on which the tape is wound.
The magnetic tape controller lO also includes two magnetic heads 35 and 36 spaced along the magnetic tape in the stretch between the two sprockets 30. The heads 35 and 36 are aligned with that magnetic track on the tape 20 which is the record of the railway track alignment.
A further magnetic head 37 located at tlle same longitudinal position as head 36 is aligned with that magnetic track on the tape 29 which is the record of the railway track crosslevel. The head 37 is shown facing the underside of the magnetic tape 29 for ease of illustration but it is to be understood that i.t would, in practice, be facing the same side of tape 29 as heads 35 and 36. The spacing between head 35 and heads 36 and 37 is shosen so that it corresponds to a desired length of track, say 10 meters. Thus, tho points A and B on the track 25 would correspond to points A' and B' on the tape 29.
Connecting lines 40 and 41 are shown interconnectillg sprockets 30 with heads 35 and 36 respectively and these are intendecl to indicate that the read heads are switched on at predetermined amounts of rotation of the sprockets 30 corresponding to predetermined 1engths on the track, say 2 meters. Thus, the read heads 35 and 36 provide outputs which represent the geometric alignment condition at every 2 meters of the track length under investigation. The actual means by which the heads are switched on is not shown but it should be appreciated that this could take the form of a cam mounted on the sprocket 30 operating a follower to open and close a switch in the heads.
The microprocessor 11 includes a ten point averager 44 to which the outputs from head 35 are fed. The averager 44 includes a digital co~ter which sums every ten outputs and divides by ten to obtain an average digital value which represents the average misalignment or deviation over a twenty meter lcngth. By successively dropping off the last input and adding a new input a running average is obtained and this is fed to the comparator 45 where it is compared with the outputs of the read head 36 which represents the actual values of track misalignment as measured from the tape 29. Because of the spacing chosen between heads 35 and 36, each reading obtained at head 36 is compared with comparator 45 with the average value of the readings corresponding to ten meters on each side of point B.
An error signal is derived in comparator 45, this error signal indicating digitally how much the track deviates from a preferred alignment condition (the average value). This error signal is converted in a digital/ analog converter 46 to provide an analog voltage which drives a servo-valve 47 controlling a hydraulic jack 48 located at the point B which corresponds to the point B' on the tape 29. Thus, the jack 48 is moved to the right or left iTI accordance with the magnitude and sign of the analog error signal in a sensc to reduce or remove the error. The digital/analog converter 46 is equivalent in function to digital analog converter 12 shown in Figure 1 and the servo-valvc 47 is equivalent to the alignment control 15 of Figure 1.
Correction of the cross-level is obtained using as a starting point the following formula, according to the A.R.A. standard, for -Ll~ 3 the superelevation of a railroad track where superelevation means the height of the outside rail on a curve above the inside rail.
The formula is E = 0.0007V D where E = the superelevation in inches V = the proposed train speed in miles per hourJ and D = the curvature of the track in degrees measured as the angle subtended by the radii from a 100 foot chord.
The output from the ten point averager 4~ is obviously a measure of the track curvature and so this output is fed to a comparator 50.
A second input to the comparator S0 is derived from a track speed adjuster 57. If the proposed train speed is, for example, 60 miles/hr., this value is selected on the track speed adjuster 51 and an appropriate signal is fed into comparator 50.
A third input to comparator 50 is derived from read head 37 which, as stated above, is aligned with the cross-level magnetic record on tape 29. As with heads 35 and 36, head 37 is understood to be related to the angular position of sprockets 30 so that a reading is obtained every few cms or so corresponding to every 2 meters of the railroad trac~. The comparator compares the signals obtained from read head 37 with 0.0007V2D obtained on the basis of the other two inputs and any resultant signal denotes the magnitudc of the track super-elevation error. The error signal thus obtained as ~n output from comparator 50 is, of course, a digital signal and so a digital/analog converter 52 is provided to derive an output analog signal which drives a servo-valve to operate a hydraulic lifting jack 54 or 55, both located ll~U393 at point B, depending on which rail has to be lifted to remove the error signal.
When the track correction machine is operating on a straight section of track the value for D is, of course zero, and therefore the computed value 0.0007V2D representing superelevation is ~ero.
Thus the cross-level should also be zero, i.e. both rails at same height, on straight track. If the cross-level as indicated by read head 37 is not zero for a straight section of track the signal obtained from servo-valve 53 controls the jacks 54 and 55 so as to reduce the cross-level towards zero.
As a modification of the above system, it is envisaged that, instead of using a single tape containing the actual record from which, using the ten point averager 44, a preferred or desired condition is obtained and simultaneously compared with the actual values on the tape, two tapes may be used, one bearing the actual record of the track condition and the other bearing the desired condition.
The second tape would have been obtained at some earlier stage by processing the first tape using, for example, a read head a ten point averager and a write head.
l~e two tapes would, in the track correction machine, be run in synchronism and there would be two read heads, one for each tape, both correspon(ling to read head 36. Thus, the comparator ~
would have an input from one read llead as beforo indicating the actua]
track condition and, instead of an input from a ten point averager, the second input would come directly from the other read head reading the second tape.
A further modification of the above system can be employed wherein the tape containing the actual record is used with a ten point 1~4V393 averager 44 to create a preferred or desi.red condition signal which is compared with the actual record to create a single tape of track error to be used on the track correction machine which would be driven in synchronism with the reading of the single tape of track error.
It will be appreciated that the original t~pe bearing a record of the track condition was obtained from a recording car operating at a particular speed and axle loading over the section of track of interest. It can be appreciated that the record obtained may, therefore, be dependent on these two parameters and so it might be useful to try to ensure that the speed and axle loading of the recording car are similar to the speed and axle loading expected in normal operation of the track. It may also be useful to obtain several tapes representing track conditions for several different axle loadings and/or vehicle speeds in the event that it expected that the track will be used over a range of axle loadings and/or speeds. In this case, it is envisaged that the several tapes will be run simultaneously and the average value of the several records at each point obtained. The average values of the several records would then be ton point averaged as before to provide a running average which would be compared with the "actual" average value of the several records. This averaging and subsequent ten point averaging could conceivably be done directly from the several tapes carried in the track correction vehicle hut it is more likely that the several tapes would bc used to provide a first "master" tape representing the average at each point of the several tapes and a second "master" tape representing the ten point averaged version of the first "master" tape. The two "master" tapes would then be processed in the track correction vehicle as described in the modification of the preceeding paragraph.
As a further modification of the basic system, the magnetic tape 29 would be used to obtain the desired or preferred geometric condition of the track but would not be used to provide the actual geometric condition of the track for comparison with the desired condition. In other words, the read heads 36 and 37 would not be used to pick off values for actual alignment and cross-level. The actual values would be obtained directly by the track correc-tion vehicle using known measuring systems for measuring the alignment and cross-level of the track and sampling the actual measurements obtained every two meters. The sampled values of track alignment and cross-level would then be fed into comparators 45 and 50, respectively. This modified system could therefore be considered as a hybrid of the basic system described above in which the original tape provides all the data necessary for track correction and the system described in our Canadian Patent No. 1,104,339 which issued July 7, 1981 and our Canadian Patent No. 1,107,060 which issued August 18, 1981, in which all the data necessary for track correction is provided by track measuring systems.
It should be appreciated that the reason for averaging ten (or so) alignment readings in the ten point average 44 is to provide an acceptable datum on a curved section of track from which to measure the alignment devia-tion of the track. An error signal can then be generated as described above.
However, on straight sections of track the datum for measuring thc deviation is obviously a straight line so that for strai~ht sections it is not neccssary to generate a datum by averaging. Tllus, the inforlllation on thc digital tapc 4could, for straight sections of track, be uscd directly as the error signal.
Although preferrcd embodiments of thc invention have been describcd, numerous modifications and alterations thereto wouLd be )393 apparent to one skilled in the art without departi.ng from the spirit and scope of the presènt inventiOTI.
Such a technique is known in which a survey of a track is made and pen chart recorder makes a recording of the track representing the condition of the track before alignment. A skilled operator then takes the recording and draws a "best line" through the recorded curve to average out the errors. The corrected record is then used in a track aligning apparatus which makes use of a photocell/potentiometer/shadow board technique for aligning the surveyed track.
In another known technique an optical record is obtained during survey of the track and this can be compared with a "standard"
optical record, for example by simiimultaneous screening. Here again, a skilled operator is necessary to interpret the differences between the actual and the ideal curves.
Both of the above techniques have the disadvantage that the alignment information fed to the track aligning machine is not mathematically accurate but is dependent on the skill and experience of the operator.
Accordingly, it is an object of the present invention to provide a technique for correcting track which is not dependent on the skill of the operator.
Another object of the invention is to provide a method of correcting a track using a record of the actual geometric conditions of the track under dynamic loading conditions.
It is a further object of the invention to provide a techni(lue for correcting track errors in which an ideal or desired condition is compared with the actual record to derive appropriate error signals.
According to a broad aspect of the invention a method of ~14~93 correcting railroad track comprises passing a recording car along the track at a predetermined speed and axle loading related to the speed and axle loading experienced by the track when in normal operation to obtain a record on a recording medium representing the actual geometric condition of at least one parameter of a length of track under predetermined dynamic loading conditions, processing electronically the record to obtain a desired geometric condition, comparing the actual geometric condition with the desired geometric condition to derive error signals indicative of the difference between the actual geometric condition and the desired geometric condition and using the error signals in a track correction vehicle to control track moving means on the track correction vehicle in a direction to reduce the difference.
In the case of a straight section of track, the first record can be used to derive the error signals without any processing step but for curved sections of track where the alignment is the parameter under consideration the first record has to be processed to obtain a desired geometric condition or a desired geometric condition has to be obtained in some other way.
The desired geometric condition may be recorded on a recording medium to obtain a record of the desired geometric condition, this record then being compared with the first mentioned record.
Alternatively, the step of obtaining a second record may be omitted, the desired geometric condition being immediately compared with the record representing the actual values of the track condition.
One way of obtaining the desired geometric condition is to compute electronically a running average value using, say, ten readings from the actual record representing track. values at 2 meter intervals.
The invention will now be described in greater detail with reference to the accompanying drawings, in which:
Figure 1 is a block diagram illustrating schematically the general system of the present invention; and Figure 2 is a schematic diagram of the invention as applied to a section of track and illustrating an exemplary embodiment of central processing unit.
The components shown in Figure 1 may be divided into three categories, namely input 1, central processing unit 2 and outputs 3. The main input may be a digital magnetic tape 4 or an FM magnetic tape 5. In either case the tape has been derived previously in known manner from a known track recording car running over a particular section of track. Such a tape typically carries separate spaced tracks each carrying a record of a specific parameter indicative of the geometric condition of the track. Thus, the tape would have records of the alignment, left rail elevation right rail elevation, cross level etc.
Another input is obtained from a block 6 entitled distance synchronization which ensures that the information on the tape is processed in synchronism with the movement of a track correction vehicle which carries the apparatus of Figure l over the section of track to be corrected. The track correction vehicle carries in known manner hydraulic mechanisms for moving ~he ~rack to the left or right and for raising the left and right rails independently. The block 7 entitled track position sensors symbolises sensors which run on the rails and derive input signals corresponding to particular locations sensed on the track, for example crossings.
With reference to the central processing unit 2, a magnetic tape controller lO under the control of a microprocessor ll controls the running of the digital tape 4. The input from ~he distance synchronization is fed to the microprocessor ll which causes the magnetic tape controller lO to control the speed of the magnetic tape 4 according to the speed of the track correction vehicle so that the tape is unwinding in synchronism with the movement of the vehicle.
The digital information on the tape is read in the magnetic tape controller and passed to the microprocessor ll which has been pre-programmed to derive a digital output signal representative of the difference between the data read at a particular point on the tape and data indicative of an ideal or preferred track condition.
It should be understood that probab]y not all the recorded information on the tape would be read and, for the purpose oE the present explanation, we will consider that the information which is being read is the track alignment record and the cross-level record. A dlgital output signal for the difference between the actual and preferred track a~ignment condition would, therefore, be obtained and further cligital output signal for the difference between the actual and preferred cross-level condition would therefore, be obtained. These cligital output signals are fed to a digital/analog converter 12 to derive analog "error"
V3~'3~
signals for controlling the track corr0ction mechanisms on the track correction vehicle.
The analog/digital converter 13 also sho~n as forming part of the central processing unit 2 is used to convert the analog input from the track position sensors 7 to digital form for handling by the microprocessor. The analog/digital converter 13 is also capable of providing suitable digital input if the track record is provided in the form of FM magnetic tape 5 rather than digital magnetic tape.
The input from the track position sensors is processed in the microprocessor 11 which then alerts the track correction vehicle to stop at crossings, for example. The use of such track position sensors for this purpose is conventional and, accordingly, will not be described in any further detail.
The digital/analog converter 12 derives output signals correspond-ing to the deviation of the track from the preferred or ideal values in respect of the parameters of interest, in the present example alignment and cross-level. Thus a box 15 entitled alignment control symbolizes a servo-mechanism for driving the track alignment mechanism either right or left depending on the alignment error signal input from the digital analog converter. Two boxes 16 and 17 cntitled left surface control and right surface control symbolize servo-mechanisms for driving lifting mechanisms for the left and right rails, respectivoly. If the cross-level "error" signal indicates that the left rail should be higher, then a signal a~pears at the input of the left surface control 16 causing the left rail to be lifted a certain amount, and, similarly, for an error signal indicating that the right rail should be higher, a signal appears on the input of the right surface control 17.
-~140393 A visual comyarator 20 may also be provided in the outputs 3 to give the operator a visual indication of, for example, the actual track condition, the preferred track condition and/or the error condition.
The visual comparator could take the form of an oscilloscope to which signals rom the microprocessor 11 and the digital analog converter 12 are applied as inputs ~hus deriving on the oscilloscope screen, three traces corresponding, respectively, to the actual track condition as recorded on the magnetic tape, the preferred track condition as obtained in the microprocessor and the "error" condition as obtained from the output of the digital/analog converter. Obviously, if a track error record is made independently from the track correction vehicle for use therein, the actual track condition and the preferred track condition could be dispensed with an only the error record would be displayed. Obviously the track alignment condition and/or the cross-level condition or any other parameter could be displayed either simultaneously or as alternatives.
The last box 21 in the outputs symolizes failure alarms which would operate if there was a power failure or a failure in any portion of the central processing unit 2 such as the microprocessor 11 or digital/ analog converter 12. The alarms would also bc capable of signalling incorrect operation of the track position sensors 7.
The alarms 21 would be arranged in known manner, on a console for monitoring by the operator.
Turnin~ now to Figure 2, an example of how the microprocessor may be programmed to obtain a preferred track condition is illustrated.
A portion 25 of a track which is to be corrected in alignment and cross-level is shown. The distance synchronization 6 is shown connected to a vehicle wheel 26 running on the track and may be in the form of a tachogenerator deriving a voltage dependent on the speed of the track correction vehicle. In that case, the output of the distance synchronisation 6 is fed to a voltage divider 27 which derives an output voltage the magnitude of whicll is dependent on the voltage from the distance syncl1ronization 6. The output voltage with appropriate amplification ~no~ shown) is used to control the tape drive 28 which forms part of the magnetic tape controller 10 and which drives the magnetic tape 29 by means of sprockets 30 on which the tape is wound.
The magnetic tape controller lO also includes two magnetic heads 35 and 36 spaced along the magnetic tape in the stretch between the two sprockets 30. The heads 35 and 36 are aligned with that magnetic track on the tape 20 which is the record of the railway track alignment.
A further magnetic head 37 located at tlle same longitudinal position as head 36 is aligned with that magnetic track on the tape 29 which is the record of the railway track crosslevel. The head 37 is shown facing the underside of the magnetic tape 29 for ease of illustration but it is to be understood that i.t would, in practice, be facing the same side of tape 29 as heads 35 and 36. The spacing between head 35 and heads 36 and 37 is shosen so that it corresponds to a desired length of track, say 10 meters. Thus, tho points A and B on the track 25 would correspond to points A' and B' on the tape 29.
Connecting lines 40 and 41 are shown interconnectillg sprockets 30 with heads 35 and 36 respectively and these are intendecl to indicate that the read heads are switched on at predetermined amounts of rotation of the sprockets 30 corresponding to predetermined 1engths on the track, say 2 meters. Thus, the read heads 35 and 36 provide outputs which represent the geometric alignment condition at every 2 meters of the track length under investigation. The actual means by which the heads are switched on is not shown but it should be appreciated that this could take the form of a cam mounted on the sprocket 30 operating a follower to open and close a switch in the heads.
The microprocessor 11 includes a ten point averager 44 to which the outputs from head 35 are fed. The averager 44 includes a digital co~ter which sums every ten outputs and divides by ten to obtain an average digital value which represents the average misalignment or deviation over a twenty meter lcngth. By successively dropping off the last input and adding a new input a running average is obtained and this is fed to the comparator 45 where it is compared with the outputs of the read head 36 which represents the actual values of track misalignment as measured from the tape 29. Because of the spacing chosen between heads 35 and 36, each reading obtained at head 36 is compared with comparator 45 with the average value of the readings corresponding to ten meters on each side of point B.
An error signal is derived in comparator 45, this error signal indicating digitally how much the track deviates from a preferred alignment condition (the average value). This error signal is converted in a digital/ analog converter 46 to provide an analog voltage which drives a servo-valve 47 controlling a hydraulic jack 48 located at the point B which corresponds to the point B' on the tape 29. Thus, the jack 48 is moved to the right or left iTI accordance with the magnitude and sign of the analog error signal in a sensc to reduce or remove the error. The digital/analog converter 46 is equivalent in function to digital analog converter 12 shown in Figure 1 and the servo-valvc 47 is equivalent to the alignment control 15 of Figure 1.
Correction of the cross-level is obtained using as a starting point the following formula, according to the A.R.A. standard, for -Ll~ 3 the superelevation of a railroad track where superelevation means the height of the outside rail on a curve above the inside rail.
The formula is E = 0.0007V D where E = the superelevation in inches V = the proposed train speed in miles per hourJ and D = the curvature of the track in degrees measured as the angle subtended by the radii from a 100 foot chord.
The output from the ten point averager 4~ is obviously a measure of the track curvature and so this output is fed to a comparator 50.
A second input to the comparator S0 is derived from a track speed adjuster 57. If the proposed train speed is, for example, 60 miles/hr., this value is selected on the track speed adjuster 51 and an appropriate signal is fed into comparator 50.
A third input to comparator 50 is derived from read head 37 which, as stated above, is aligned with the cross-level magnetic record on tape 29. As with heads 35 and 36, head 37 is understood to be related to the angular position of sprockets 30 so that a reading is obtained every few cms or so corresponding to every 2 meters of the railroad trac~. The comparator compares the signals obtained from read head 37 with 0.0007V2D obtained on the basis of the other two inputs and any resultant signal denotes the magnitudc of the track super-elevation error. The error signal thus obtained as ~n output from comparator 50 is, of course, a digital signal and so a digital/analog converter 52 is provided to derive an output analog signal which drives a servo-valve to operate a hydraulic lifting jack 54 or 55, both located ll~U393 at point B, depending on which rail has to be lifted to remove the error signal.
When the track correction machine is operating on a straight section of track the value for D is, of course zero, and therefore the computed value 0.0007V2D representing superelevation is ~ero.
Thus the cross-level should also be zero, i.e. both rails at same height, on straight track. If the cross-level as indicated by read head 37 is not zero for a straight section of track the signal obtained from servo-valve 53 controls the jacks 54 and 55 so as to reduce the cross-level towards zero.
As a modification of the above system, it is envisaged that, instead of using a single tape containing the actual record from which, using the ten point averager 44, a preferred or desired condition is obtained and simultaneously compared with the actual values on the tape, two tapes may be used, one bearing the actual record of the track condition and the other bearing the desired condition.
The second tape would have been obtained at some earlier stage by processing the first tape using, for example, a read head a ten point averager and a write head.
l~e two tapes would, in the track correction machine, be run in synchronism and there would be two read heads, one for each tape, both correspon(ling to read head 36. Thus, the comparator ~
would have an input from one read llead as beforo indicating the actua]
track condition and, instead of an input from a ten point averager, the second input would come directly from the other read head reading the second tape.
A further modification of the above system can be employed wherein the tape containing the actual record is used with a ten point 1~4V393 averager 44 to create a preferred or desi.red condition signal which is compared with the actual record to create a single tape of track error to be used on the track correction machine which would be driven in synchronism with the reading of the single tape of track error.
It will be appreciated that the original t~pe bearing a record of the track condition was obtained from a recording car operating at a particular speed and axle loading over the section of track of interest. It can be appreciated that the record obtained may, therefore, be dependent on these two parameters and so it might be useful to try to ensure that the speed and axle loading of the recording car are similar to the speed and axle loading expected in normal operation of the track. It may also be useful to obtain several tapes representing track conditions for several different axle loadings and/or vehicle speeds in the event that it expected that the track will be used over a range of axle loadings and/or speeds. In this case, it is envisaged that the several tapes will be run simultaneously and the average value of the several records at each point obtained. The average values of the several records would then be ton point averaged as before to provide a running average which would be compared with the "actual" average value of the several records. This averaging and subsequent ten point averaging could conceivably be done directly from the several tapes carried in the track correction vehicle hut it is more likely that the several tapes would bc used to provide a first "master" tape representing the average at each point of the several tapes and a second "master" tape representing the ten point averaged version of the first "master" tape. The two "master" tapes would then be processed in the track correction vehicle as described in the modification of the preceeding paragraph.
As a further modification of the basic system, the magnetic tape 29 would be used to obtain the desired or preferred geometric condition of the track but would not be used to provide the actual geometric condition of the track for comparison with the desired condition. In other words, the read heads 36 and 37 would not be used to pick off values for actual alignment and cross-level. The actual values would be obtained directly by the track correc-tion vehicle using known measuring systems for measuring the alignment and cross-level of the track and sampling the actual measurements obtained every two meters. The sampled values of track alignment and cross-level would then be fed into comparators 45 and 50, respectively. This modified system could therefore be considered as a hybrid of the basic system described above in which the original tape provides all the data necessary for track correction and the system described in our Canadian Patent No. 1,104,339 which issued July 7, 1981 and our Canadian Patent No. 1,107,060 which issued August 18, 1981, in which all the data necessary for track correction is provided by track measuring systems.
It should be appreciated that the reason for averaging ten (or so) alignment readings in the ten point average 44 is to provide an acceptable datum on a curved section of track from which to measure the alignment devia-tion of the track. An error signal can then be generated as described above.
However, on straight sections of track the datum for measuring thc deviation is obviously a straight line so that for strai~ht sections it is not neccssary to generate a datum by averaging. Tllus, the inforlllation on thc digital tapc 4could, for straight sections of track, be uscd directly as the error signal.
Although preferrcd embodiments of thc invention have been describcd, numerous modifications and alterations thereto wouLd be )393 apparent to one skilled in the art without departi.ng from the spirit and scope of the presènt inventiOTI.
Claims (11)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of correcting railroad track comprising passing a recording car along the track at a predetermined speed and axle loading related to the speed and axle loading experienced by the track when in normal operation to obtain a record on a recording medium representing the actual geometric con-dition of at least one parameter of a length of track under predetermined dynamic loading conditions, processing electronically the record to obtain a desired geometric condition, comparing the actual geometric condition with the desired geometric condition to derive error signals indicative of the difference between the actual geometric condition and the desired geometric condition and using the error signals in a track correction vehicle to control track moving means on the track correction vehicle in a direction to reduce the difference.
2. A method of correcting railroad track comprising passing a recording car along the track at a predetermined speed and axle loading related to the speed and axle loading experienced by the track when in normal operation to obtain a record on a recording medium representing the actual geometric con-dition of at least one parameter of a length of track under predetermined dynamic loading conditions, transferring the record to a track correction vehicle, passing the track correction vehicle along the track while synchronously reading the record and processing electronically the record to obtain a desired geometric condition, simultaneously comparing the actual geometric condition on the record with the desired geometric condition obtained to derive error signals indicative of the difference between the actual geometric condition and the desired geometric condition and using the error signals in the track correction vehicle to control track moving means on the track correction vehicle in a direction to reduce the difference.
3. A method of correcting railroad track comprising passing a recording car along the track at a predetermined speed and axle loading related to the speed and axle loading experienced by the track when in normal operation to obtain a record on a recording medium representing the actual geometric condi-tion of at least one parameter of a length of track under predetermined dynamic loading conditions, transferring the record to a track correction vehicle, passing the track correction vehicle along the track while synchronously reading the record and processing electronically the record to obtain a desired geometric condition, synchronously measuring directly from the track the actual geometric condition and simultaneously comparing the actual geomet-ric condition obtained directly with the desired geometric condition obtained to derive error signals indicative of the difference between the actual geomet-ric condition and the desired geometric condition and using the error signals in the track correction vehicle to control track moving means on the track correction vehicle in a direction to reduce the difference.
4. A method according to claim 2 or claim 3, in which, for correcting alignment, the desired geometric condition is obtained by computing electron-ically from the record a running average value which is then immediately compared with the actual geometric condition on the record.
5. A method of correcting railroad track comprising passing a recording car along the track at a predetermined speed and axle loading related to the speed and axle loading experienced by the track when in normal operation to obtain a first record on a recording medium representing the actual geometric condition of at least one parameter of a length of track under predetermined dynamic loading conditions, processing electronically the first record to ob-tain a second record representing a desired geometric condition, transferring the first and second records to a track correction vehicle, passing the track correction vehicle along the track while synchronously reading and comparing the first and second records to derive error signals indicative of the difference between the actual geometric condition and the desired geometric condition and Using the error signals in the track correction vehicle to control track moving means on the track correction vehicle in a direction to reduce the difference.
6. A method of correcting railroad track comprising passing a recording car along the track at a predetermined speed and axle loading related to the speed and axle loading experienced by the track when in normal operation to obtain a first record on a recording medium representing the actual geometric condition of at least one parameter of a length of track under predetermined dynamic loading conditions, processing electronically the first record to obtain a desired geometric condition, and simultaneously comparing this desired geo-metric condition with the actual geometric condition on the first record to obtain a second record of track error, transferring the second record to a track correction vehicle, passing the track correction vehicle along the track while synchronously reading the second record to derive error signals indicative of the difference between the actual geometric condition and the desired geometric condition and using the error signals in the track correction vehicle to control track moving means on the track correction vehicle in a direction to reduce the difference.
7. A method according to claim 5 or 6, in which, for correcting align-ment, the step of electronically processing the first record comprises com-puting electronically from the first record a running average value.
8. A method of correcting railroad track comprising passing a recording car along the track at least twice at different predetermined speeds and axle loadings related to the speed and axle loading experienced by the track when in normal operation to obtain a plurality of records on a recording medium repre-senting the actual geometric condition of at least one parameter of a length of track under a plurality of different predetermined dynamic loading conditions, averaging the plurality of records to obtain an average record, processing electronically the average record to obtain a desired geometric condition, comparing the actual geometric condition with the desired geometric condition to derive error signals indicative of the difference between the actual geo-metric condition and the desired geometric condition and using the error signals in a track correction vehicle to control track moving means on the track correction vehicle in a direction to reduce the difference.
9. A track correction vehicle for correcting at least one parameter of a length of track, comprising a record reading system adapted to read a first record on a recording medium representing the actual geometric conditions of at least one parameter of the length of track, the record reading system having record drive means synchronised with the vehicle speed whereby electrical error signals indicative of the difference between the actual geometric conditions and the desired geometric condition are derived, and track moving means operable under control of the electrical error signals to move the track in a direction to reduce the difference.
10. A track correction vehicle according to claim 9 in which, for correc-ting alignment, the record reading system comprises an upstream and a downstream read head mutually spaced a predetermined distance along the direction of travel of the recording medium which distance corresponds to a predetermined length of track, means for sampling at both heads the alignment record at predetermined intervals, the upstream read head having an output connected to an averaging circuit which derives at an output thereof a running average of a plurality of samples, the output of the averaging circuit and an output of the downstream read head being connected to a comparator which derives electrical error sig-nals controlling track moving means to correct the alignment.
11. A track correction vehicle according to claim 10 comprising a further read head adjacent the downstream read head for alignment with the cross-level record, the further read head having an output providing samples of cross-level readings at predetermined intervals to a further comparator, an output of the averaging circuit also being connected to the further comparator in which values of superelevation corresponding to track curvature are obtained and compared to the cross-level samples to derive error signals, and means for raising one rail relative to the other under the control of the error signals to achieve the correct superelevation.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US95660078A | 1978-11-01 | 1978-11-01 | |
| US956,600 | 1978-11-01 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1140393A true CA1140393A (en) | 1983-02-01 |
Family
ID=25498426
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000337666A Expired CA1140393A (en) | 1978-11-01 | 1979-10-16 | Method and apparatus for correcting railroad track using a dynamic loading record of track condition |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS5561601A (en) |
| AT (1) | ATA705079A (en) |
| AU (1) | AU535560B2 (en) |
| BR (1) | BR7907086A (en) |
| CA (1) | CA1140393A (en) |
| DE (1) | DE2943183A1 (en) |
| ES (1) | ES485568A1 (en) |
| FR (1) | FR2440440A1 (en) |
| GB (1) | GB2036379B (en) |
| IT (1) | IT7969133A0 (en) |
| ZA (1) | ZA795547B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2174216B (en) * | 1985-03-19 | 1988-10-26 | Mitutoyo Mfg Co Ltd | Method of operating a coordinate measuring instrument |
| GB9211901D0 (en) * | 1992-06-05 | 1992-07-15 | British Railways Board | Methods of railway track maintenance |
| ATE191032T1 (en) * | 1995-01-10 | 2000-04-15 | Plasser Bahnbaumasch Franz | METHOD AND TRACK CONSTRUCTION MACHINE FOR PERFORMING TRACK CONSTRUCTION WORK |
| CN104652199B (en) * | 2015-02-13 | 2016-08-24 | 中铁第一勘察设计院集团有限公司 | High speed railway track measuring instrument ruler suspended structure |
| CN104831592B (en) * | 2015-04-29 | 2016-08-24 | 安徽兴宇轨道装备有限公司 | A kind of comprehensive device for regulating rail |
-
1979
- 1979-10-16 CA CA000337666A patent/CA1140393A/en not_active Expired
- 1979-10-17 ZA ZA00795547A patent/ZA795547B/en unknown
- 1979-10-23 AU AU52083/79A patent/AU535560B2/en not_active Ceased
- 1979-10-25 DE DE19792943183 patent/DE2943183A1/en not_active Withdrawn
- 1979-10-30 FR FR7926860A patent/FR2440440A1/en active Granted
- 1979-10-30 JP JP14041079A patent/JPS5561601A/en active Pending
- 1979-10-31 GB GB7937721A patent/GB2036379B/en not_active Expired
- 1979-10-31 BR BR7907086A patent/BR7907086A/en unknown
- 1979-10-31 ES ES485568A patent/ES485568A1/en not_active Expired
- 1979-10-31 IT IT7969133A patent/IT7969133A0/en unknown
- 1979-10-31 AT AT0705079A patent/ATA705079A/en not_active Application Discontinuation
Also Published As
| Publication number | Publication date |
|---|---|
| GB2036379A (en) | 1980-06-25 |
| FR2440440A1 (en) | 1980-05-30 |
| ATA705079A (en) | 1983-03-15 |
| ZA795547B (en) | 1980-10-29 |
| DE2943183A1 (en) | 1980-05-14 |
| GB2036379B (en) | 1982-12-01 |
| AU5208379A (en) | 1980-05-08 |
| JPS5561601A (en) | 1980-05-09 |
| AU535560B2 (en) | 1984-03-29 |
| ES485568A1 (en) | 1980-06-16 |
| IT7969133A0 (en) | 1979-10-31 |
| BR7907086A (en) | 1980-06-17 |
| FR2440440B1 (en) | 1983-03-18 |
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