TM 5-628/AFR 91-44
a. Definition. Warp is the difference in crossle-
vel between any two points less than or equal to 62
feet. Warp is determined as follows:
(1) Use the line rail as the reference rail.
(2) Measure the crosslevel at any two points
less than 62 feet apart, normally at joints in the rail.
If the reference rail is lower than the opposite rail,
the sign of the measurement is negative (-). If the
reference rail is higher than the opposite rail, the
sign of the measurement is positive (+).
(3) To determine warp. If both signs are the
same, drop the signs and subtract the smaller
measurement from the larger measurement. If the
signs are different, drop the signs and add the
measurements. Figure 12-4 presents an example of
the warp calculation.