49 CFR § 213.115 - Rail end mismatch.

§ 213.115 Rail end mismatch.

Any mismatch of rails at joints may not be more than that prescribed by the following table -

Class of track Any mismatch of rails at joints may not be more than the following -
On the tread of the rail ends (inch) On the gage side of the rail ends (inch)
Class 1 track 1/4 1/4
Class 2 track 1/4 3/16
Class 3 track 3/16 3/16
Class 4 and 5 track 1/8 1/8