MW&S STANDARD PROCEDURE

Transcription

1 FILE 1 of 6 SCOPE AND NATURE To provide for a uniform system of adjusting both jointed and welded rail for the prevention of buckling track where the rail was laid outside the preferred rail temperature range. SPECIAL REFERENCES NS Safety and General Conduct Rules Book Standard Procedure Rail Anchors Standard Procedure Safe Abrasive Rail Sawing and Grinding Practices Standard Procedure Maintaining Track Stability Electronic Rail Added/Removed reporting screen ] Copy attached to procedure OUTLINE OF PROCEDURE Begins on 1. GENERAL CALCULATING LENGTH ADJUSTMENT PREPARATION FOR ADJUSTING RAIL SLOW ORDERS LOCATION OF CUTTING WELDED RAIL FOR ADJUSTMENT... 3 Begins on 6. SHORTENING WELDED RAIL SHORTENING JOINTED RAIL LENGTHENING WELDED RAIL ADJUSTING RAIL IN PANDROL PLATES REPORTING... 6

2 FILE 2 of 6 PROCEDURE 1. GENERAL.01 The preferred rail laying temperature range is 85 F to 100 F, ideally 95 F..02 As an aid in determining where rail may need adjustment, the temperatures should be reviewed on the monthly reports of Program Maintenance production that is furnished to the division engineers by the manager programs and schedules..03 Reviewing of these monthly reports, particularly the rail laying temperatures for rail laid and other locations where joints have been created in CWR that are BELOW the preferred rail laying temperature, and particularly below 75 F, along with visual inspection of the track can indicate welded rail that may need to be shortened to prevent buckling in hot weather due to excessive thermal expansion..04 When track is known to be tight or has moved out of line at the end of a bridge where expansion joints do not exist, it is necessary that rail be cut and adjusted in order to relieve stresses in the track rather than by lining the track..05 Rail is to be adjusted by cutting where repeated maintenance is required to maintain alignment. a. Lining of curves outward may be required for curves which have moved inward due to low temperature from cold weather. b. Slow orders must be placed at locations subject to getting out of line until the track condition has been corrected..06 Rail laid ABOVE the preferred temperature range may require lengthening during the fall or winter to prevent undue tension stress caused by excessive thermal contraction during cold weather. inspections during cold weather. When rail is properly anchored with anchors of the required strength, abnormally wide rail gaps at joints indicate excessive tension and track should be carefully watched for further indications of yield at joints. Actual "pull-apart at joints or welds, is positive indication that lengthening is required..08 In all cases where rail is either shortened or lengthened, care must be taken to confine the adjustment to the amount actually needed. Severe rail stress in the opposite direction may occur later if excessive adjustment is made..09 The track supervisor or individual designated by the division engineer must be with any Line Maintenance forces adjusting welded rail. 2. CALCULATING LENGTH ADJUSTMENT.01 The theoretical amount that rail is shortened or lengthened is calculated by the formula: L x D x x 12 = Length Adjustment (in inches) Where: L = Length (in feet)of welded rail to be adjusted. D = Difference (in degrees F) between preferred rail temperature and actual rail temperature at time rail was laid. EXAMPLE: Welded rail in 1440 foot lengths was laid at a rail temperature of 40 F and the preferred temperature is 95 F. The rail laid at 40 F is 55 F degrees below the preferred temperature. Therefore, the theoretical amount that the rail should be shortened is: L x D x x 12 = Length Adjustment (in inches) 1440 x 55 x x 12 = 6.27 inches.07 Rail laid under the conditions described in 1.06 should have frequent and careful

3 FILE 3 of 6.02 On all main tracks and sidings where CWR is installed and all other tracks class 2 and above where CWR is installed; any rail that has been broken, cut for defect removal or disjoined for other repairs below the preferred temperature range may need to be readjusted to within the designated rail temperature range. Refer to Standard Procedure PREPARATION FOR ADJUSTING RAIL.01 Arrangements must be made with appropriate Transportation Department employees for necessary track time..02 If the track is in signal territory, advance arrangements must be made with the C&S Department for protection of signal system. 4. SLOW ORDERS.01 A slow order of 10 mph maximum speed is required for all adjustment operations including cutting rail and removing anchors..02 All cribs from the anchor re-application must be filled and track inspected before removing slow order..03 If the ties were disturbed in their bed during the rail adjustment process, then the provisions of Standard Procedure 390 Maintaining Track Stability regarding slow orders for Surfacing Track without a stabilizer must be observed. 5. LOCATION OF CUTTING WELDED RAIL FOR ADJUSTMENT.01 Before any length adjustment is made in rail, preliminary observations should be made to determine in which direction rail has a tendency to run. The shortening of any given length of rail should be done at the end toward which rail is running. Lengthening or adding rail should be done at the end where there is indication of pull apart. If there appears to be no particular direction the rail is running, the adjustment should be done towards the center of the segment to be adjusted..02 If joints exist, and other conditions permit, the cut should be at the joint..03 If a cut is made at a thermite weld or plant weld, the entire weld including a minimum of NINE inches on EACH side of the center line of a thermite weld or TWELVE inches on EACH side of the center line of a plant weld must be removed in order to eliminate all traces of the heat affected zone. Under no circumstances is a weld allowed to be in the confines of joint bar following the adjustment of rail. *.04 Unless conditions absolutely require, welded rail should not be cut within six rail lengths (234 feet) of or be cut on an open deck bridge. If it is absolutely necessary to cut welded rail in such a location, it must be slow ordered until field welded and weld is tested and accepted. Field welds should be made within three days. 6. PROCEDURE FOR SHORTENING WELDED RAIL.01 When adjusting welded rail, the cut should be not more than 900 feet from the end limits of the rail segment to be adjusted thereby adjusting not more than 1800 feet of total rail with one cut. Depending upon track conditions, a lesser amount of rail may only be able to be adjusted..02 If reference marks do not already exist, then place the reference marks on the rail prior to cutting in order to be able to measure the amount of rail removed upon completion of the rail adjustment. Refer to Section 10 Reference Mark Procedures.

4 FILE 4 of 6.03 The rail should be marked each quarter of the segment that anchors are removed to ensure that the rail has moved uniformly toward the cut. EXAMPLE: If 4 inches of rail is to be removed from 1,600 feet of rail that is adjusted at the center, then 2 inches must come from each 800 foot segment. The rail should move: at the cut 2 inches 200 feet from cut 1-1/2 inches 400 feet from cut 1 inch 600 feet from cut 1/2 inch.04 Whenever possible, the cut should be made in the cool part of the day before thermal expansion has put rail in compression..05 If rail must be cut in the hot part of day when rail is in compression, a cutting torch must be used to relieve pressure. a. When cutting the rail, NO one is allowed to stand in the gage of the track. b. All spikes must remain on both sides of the rail to prevent the rail from buckling out of the plates. c. Cut section out of ball of rail. d. Cut section out of base of rail. e. Remove web of rail by melting as rail ends move together. f. The burned ends must be SAW cut a minimum of two inches beyond the torch cut rail ends in order to prevent hairline cracks and rail end failures from uneven cooling. *.06 After the rail is saw cut, and unless the rail is to be immediately field welded, the rail ends should be drilled using a template and barred using two bolts in each rail end. If the joint is not field welded within 60 days the joint must be box anchored every effective tie for six 39 ft rail lengths (234 ft) on each side of joint, or six bolts installed..07 If the adjustment is being made from both directions from the cut, remove the rail anchors, or drive back a sufficient amount to allow rail movement, in both directions for the limit of the segment of track being adjusted after the cut is made.08 If necessary, such as newly laid rail, raise spikes slightly to prevent rail from hanging on the plates and spikes..09 Tap or vibrate rail to ensure complete movement. Train traffic is often useful to help the rail to move through the plates. Heat or rail expander may be necessary to close up the rail gap..10 If heat localized in the cut area is used to close up the rail ends, it will be necessary to wait for the rail to cool in this area before the rail will move towards the cut area from the outer limits of the segment being adjusted..11 Anchors should initially be reapplied or driven back tight beginning at the cut only on the side of the tie to prevent the rail from pulling apart from the cut until the entire segment being adjusted has reached equilibrium. The remaining anchors may then be reapplied. All anchors must be reapplied tightly to the tie with a full bearing against the side of the tie. Weak or broken anchors must be replaced. *.12 Where cuts are made on tangent track and curves less than 3 degrees and the joints are not to be field welded; within 60 days additional anchors are required to box anchor every effective tie for six rail lengths (234 feet) on each side of the joint or six bolts installed. 7. PROCEDURE FOR SHORTENING JOINTED RAIL The procedure for shortening jointed rail is the same as for welded rail except that if the rail ends are being mismatched for cutting the following instructions must be observed..01 Remove all bolts but one in the joint. The bolt remaining should be with the nut to the field side.

5 FILE 5 of 6.02 Pull the gage side spikes working away from the joint. No one is allowed to be in the gage of the track in the area spikes have been pulled prior to mismatching the rail ends..03 The last bolt with the nut to the field side is to be removed by employee standing to field side. No one is allowed in the gage of the track until the rails ends have been mismatched or it is known that the pressure has been relieved. 8. PROCEDURE FOR LENGTHENING WELDED RAIL.01 When welded rail requires lengthening (because the laying temperature is too high or too much rail was cut out in rail adjusting), the cut should be made when the rail temperature is below the preferred temperature range. Rail anchors are to be removed in both directions a sufficient distance to permit thermal contraction to open the gap to length required for insertion of short rail. The amount of rail to be added is calculated in accordance with section Rail Plug Lengths * a. The minimum plug lengths that may be used provided that the rail is field welded within two weeks from the date that the plug is placed in the track is as follows: (1) Tangent Track (welded same day unless slow ordered) 6 feet (2) Tangent Track 11 feet (3) Curves up to 4 degrees 11 feet (4) Curves 4 degrees and over 19-1/2 feet (5) Plugs longer than the above may be utilized. * b. The minimum rail length that may be left in the track as a permanent repair without field welding within two weeks is 21 feet. If the joint is not field welded within 60 days the joint must be box anchored every effective tie for six 39 ft rail lengths (234 ft) on each side of joint, or six bolts installed..03 Proper and accurate electronic reporting is essential to ensure that all locations requiring adjustment have been adjusted. 9. ADJUSTING RAIL IN PANDROL PLATES In addition to the appropriate instructions contained in 6, 7, and 8, the following instructions must also be followed..01 After determining the amount of rail to be removed, and the point of adjustment, rail is to be cut and joint applied secured by bolting one rail end only..02 Remove standard Pandrol e-clips in a direction away from the cut ends leaving clips every third tie..03 Install Pandrol zero longitudinal restraint clips in a pattern of every third tie the entire distanced of robbed track..04 Remove remaining standard Pandrol e-clips in direction away from cut rail ends. This allows the rail to destress toward cut ends..05 After sufficient rail adjustment is completed, reapply standard Pandrol e-clips in a direction from the ends of the robbed track area toward the cut rail ends replacing all Pandrol zero longitudinal restraint clips with standard Pandrol e-clips..06 Care must be taken to ensure that the e-clips and the zero longitudinal restraint clips are not mixed. Once the adjustment is completed, NO zero longitudinal restraint clips may remain in the track.

6 FILE 6 of REPORTING.01 Reference Marks The use of reference marks includes: a. Place reference marks on the rail at each end of the location to be cut or rail added. Make sure they are beyond the limits of the work. b. Measure and record the distance between reference marks. c. Cut the rail and complete the adjustment and/or rail replacement. d. Measure and record the rail temperature from the shady side of the rail. e. Measure the distance between reference marks and record. f. The difference in distance between the before and after marks is the amount of rail added or removed. g. Record the measured difference as rail added/removed and document the same including the location, rail temperature and other required information on the appropriate electronic report..02 When welded rail is adjusted, the Rail Added/Removed report found on the engineering web page must be completed in full and submitted on the same day the rail is adjusted..03 Adjustment to jointed rail does not need to be reported. APPROVED: Assistant Vice President -

7 FILE Exhibit i of i Electronic Rail Added/Removed reporting screen