CWR Flashcards
Learn CWR Policy and get good at it.
What is the maximum length for changing CWR rail without destressing?
85’
What is Continuous Welded Rail?
CWR is rail welded into lengths exceeding 400’.
What happens to CWR if joints are added later?
Once CWR is installed, it stays CWR even if joints are added later.
What is the temperature that a piece of CWR is neither in tension or compression?
Rail Neutral Temperature (RNT)
What do you have to do if rail is laid at 40 degrees or more below the TNT?
Rail must be slow ordered or destressed (this is just for laying rail, not installing a plug rail/etc)
Where do we install new anchors?
Wherever needed or necessary.
Where are anchors not required?
Where there are elastic fasteners (safelock clips, pandrol clips, Vossloh, etc)
When are anchors applied on the field side?
If GAP > PULL (i.e. rail is added) then add anchors on the field side for 3 ties in each direction.
What are the two types of anchor patterns and when do we use each?
Standard pattern - normal pattern of boxing every other tie.
Solid box anchor - pattern boxing every tie used when within 195 feet of turnouts, open deck bridges, or other ‘fixed objects’ (Can be crossing with elastic fasteners, for example)
How do you apply anchors on ballast deck bridges?
In the same pattern as the track around it.
How do you apply anchors to open deck bridges?
Apply anchors to all ties fastened to stringers.
How do we anchor around a turnout?
Box anchor the rail anchors for 195 feet ahead of a switch point and behind the heel of a frog on both the main track and the turnout side. For everywhere else, box anchor every second tie.
How do you handle legacy patterns on CWR?
On dual rail installations completed before September 21, 1998, existing anchoring may remain if rail is restrained to prevent track buckles. If restraint is not sufficient, we must adjust rail by increasing or decreasing the length of rail, by lining curves or by adding anchors to rail.
How can the RNT of a string of rail change?
Rail can creep through the fasteners due to train braking, acceleration & temperature changes (anchor/fastener condition dependent).
Curve movement due to curving forces of traffic and temperature swings.
Track settlement under traffic.
Maintenance activities.
What types of maintenance activities may cause RNT changes to CWR track?
Any track disturbance work in curves such as surfacing, tie installation or undercutting (the curve will move inward with cooler temps, outward with warmer temps).
Surfacing where vertical curves or line swings are straightened out.
Rail that is broken or cut for defect repairs or construction activities.
Cutting a plug rail in for adjustments or installations of less than 85 feet.
When is an appropriate time to add rail?
Winter months – when it’s too cold to pull out the gap.
What are the seasons when we shouldn’t add rail?
Transitioning from Spring to Summer, or in the Summer during cool spells at night causing a drastic difference in temperature between night and day.
If you show up to a broken rail and have a 20ft plug rail, how many feet apart should you make your match marks?
28 ft – 20ft plug rail plus 4’ on each side of the joints.
How far from the joint is the match mark required to be?
4ft
When should we de-stress versus pull the amount in the Rail Removal Work Order?
Best practice - if the pull is more than 2 inches, de-stress the rail.
If you’re within 400 feet of a turnout or fixed object, only remove the amount of the original gap or de-stress the rail.
If you de-stress near a fixed objects, de-stress to 10 degrees higher than the TNT.
How do we handle all rail adjustments within 400’ of a fixed object?
All rail adjustments within 400’ of fixed objects are treated one of two ways: De-stress per EI 6.2.4 or Pull the original gap amount (Pull=Gap to restore original match marks).
If rail does not get adjusted properly within the allotted time frame, what is the remedial action?
25mph slow order until properly adjusted.
Can you ever place any other type of slow order besides a 25mph when rail has not been properly adjusted prior to the temperature requirements?
Yes - you can place a 40mph slow order but the location must be inspected DAILY until it is remediated or a 25mph slow is placed.
What are three methods we adjust the rail to TNT or higher?
Using the Pull Chart or pulling the original gap whichever is greater at the time of the initial event
Rail Removal Work Order
De-stress.
What is the Rail Neutral Temperature (RNT)?
The temperature the rail is neither in tension nor compression.
What is the Target Neutral Temperature (TNT)?
The established temperature rail should be installed and maintained at for specific BNSF
areas.
What is the Temperature Differential?
The difference between area TNT and the actual rail temperature at the time of rail
installation or adjustment.
How is CWR defined? What makes rail CWR?
Welded rail that exceeds 400’, or rail installed as CWR that now has a joint, plug rail, or panels is considered CWR. Once it’s installed CWR, it’s always CWR.
What happens if rail is laid (i.e. rail gang installs it) at a temperature cooler than 40º below the target neutral temperature?
It must be adjusted or protected with a 40mph restriction.
What is anchoring CWR rail in Standard Box Pattern?
Box anchor every other tie.
What locations require solid box anchoring 195 feet in both directions?
Turnouts and open-deck bridges (essentially fixed objects).
Rail that’s been pulled apart, broken, or cut for defect removal must be readjusted to:
TNT minus 20 degrees or higher within 365 days.
You have a rail break or pull apart with a rail temperature of 20 degrees and the location hasn’t been readjusted to TNT. What do you do?
Readjust or place slow order (25mph or 40mph with daily inspection) before rail temperature hits 115 degrees.
When completing preventative maintenance on existing CWR by de-stressing the rail, what steps do you use?
You place match marks, cut the rail, knock anchors in 200ft of each direction, and use the de-stressing chart in Ch. 6 (6-3) to figure out your necessary adjustment.
When is curve staking required?
Before tie renewal, surfacing or undercutting a curve on main tracks if the curve is 2 degrees or sharper.
When curve staking is required, how do you place the stakes?
Place at least 3 stakes at the point of spiral, center of curve, and point of spiral on the other end. The reference points must be no more than 400ft apart.
If a curve has been staked per EI 8.6.3 and the curve has shifted inward more than 2”, the curve must be lined out prior to:
rail temperatures exceeding the TNT for that area.
How is Gap entered when the rail runs together?
Enter a negative number.
What should be done if it is not possible to remove the amount of rail shown on the work order
and there are no fixed objects within 400’?
If it’s not possible to remove the amount in the work order the only other acceptable repair procedure is to de-stress the rail for at least 400 feet.
The rail temperature was 0ºF when the section cut in a rail to repair a service failure. When
the welders returned to shoot the welds, the air temperature was 60ºF and rail temperature
was 70ºF. What temperature should the welders enter in the weld attributes screen?
70 degrees.
On a 75º day on a territory with a 95º TNT, welders go to a spot with a plug rail to repair a
defective rail behind the detector car and weld it. They make the first cut and the rail gaps
open 1”. The rail temperature measures 105º. What action should the welders take?
Weld the plug rail in track without pulling any rail.
What is the purpose of temporary speed restrictions for track work (Table 4-1)?
Restrictions allow the ballast to consolidate, rail compressive forces to equalize, and the subgrade to compact while ensuring safe train operations until the track stabilizes.
During the work or before returning the track to service, the supervisor or foreman in charge must ensure that:
Gage, surface and alignment have been established and the crib and shoulder ballast is in place or lateral constraint is otherwise provided and the rail is anchored sufficiently.
On April 2nd, you arrive on the Forsyth Sub at 0600. There is a Service Failure consisting of a
broken rail at MP 100.100. There’s a 2 inch gap in the rail. The rail temperature is 40 degrees,
the Pull Chart says to pull 2.75 inches, and the TNT is 95 degrees. When installing the plug rail
and before angle barring, what is the pull required to restore TNT and avoid a RRWO?
2.75” – shave off 3/4” and then pull it all out and bar it up.
Refer to Table 4-1 in Engineering Instruction 4.10 for Temporary Speed Restrictions for Track
Work. What is the requirement for spot surfacing (without Dynamic Track Stabilizer) when the
max rail temp is 105° F and greater?
1 train at 10 mph,
if track is OK, then 1 train at 10 mph
if track is OK, then 10 trains at 25 mph
If track is okay, then 10 trains at 40 mph
If track is okay, then maximum authorized speed.
The FRA requires CWR rail joint inspections. Per the CWR Procedures, what defines a CWR joint?
Any joint directly connected to CWR or any joint(s) in a segment of rail between CWR strings that are less than 195’ apart (except joints located on jointed sections on bridges)
All CWR joints within what classes of CWR track must be inspected on foot? (Section 6.1)
Any joint in Class 2 track where passenger trains operate and Class 3 or higher everywhere else.
On May 20th, when you arrive on the Red Rock Sub, you are called out to a Service Failure consisting of a rail pull apart at MP 1056.0. You have a ½ inch gap in the rail, the rail temperature is 85 degrees, and the TNT for the region is 100 degrees. Refer to the Pull Chart to
determine the pull. What action do you take to return the rail to as close as possible to TNT?
Since GAP < PULL, pull it out and bar it up.
In class 4 and 5 track what is the maximum allowable amount of mismatch at joints on the tread of the rail ends as recommended by BNSF?
1/16”
For purposes of forecasting or initiating extreme weather inspections and conversions of rail
temperatures to ambient temperatures use the following:
In hot weather rail temperature is approximately equal to ambient (air) temperature plus 30º F and in cold weather rail temperature is equal to ambient temperature.
When making a main track Hot Weather Inspection, and a tight rail condition is discovered, what is the appropriate remedial action? (CWR Procedures Section 7.1)
Restrict to 25mph or out of service until repair or adjustment is made.
How are gap and pull reported when a weld is made in bolted rail?
Report Gap and Pull the same as in CWR and select “Non-CWR or Out of Track” in the dropdown for anchor index.
You’re the foreman of the section and you go to repair the pull-apart shown on a call out.
You measure the gap between the rail ends to be 2.75”, you use a smoker rope to run the rail together enough to get a drift pin in and reinstall the bolts.
What do you enter in PARS for Gap and Pull when you report the service failure?
Gap 2.75”, pull 2.75”
When you arrive on the Forsyth Sub, April 10th, you encounter a Service Failure of a broken rail at MP 90.8. The rail temperature is 61 degrees, the TNT for the region is 95 degrees, and you have a ½ inch gap. The Pull Chart says to pull 1 ¼ inch. What action do you take to return the rail to as close as possible to TNT?
Cut out 3/4”, pull the rail and bar it.
If a Rail Removal Work Order asks you to remove 4 inches of rail, what is the best practice to fix the rail?
De-stress the rail.
