49 C.F.R. § 213.135 : Transportation — OTHER REGULATIONS RELATING TO TRANSPORTATION — FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION — TRACK SAFETY STANDARDS — TRACK STRUCTURE — Switches

(a) Each stock rail must be securely seated in switch plates, but care shall be used to avoid canting the rail by overtightening the rail braces.
(b) Each switch point shall fit its stock rail properly, with the switch stand in either of its closed positions to allow wheels to pass the switch point. Lateral and vertical movement of a stock rail in the switch plates or of a switch plate on a tie shall not adversely affect the fit of the switch point to the stock rail. Broken or cracked switch point rails will be subject to the requirements of §213.113, except that where remedial actions C, D, or E require the use of joint bars, and joint bars cannot be placed due to the physical configuration of the switch, remedial action B will govern, taking into account any added safety provided by the presence of reinforcing bars on the switch points.
(c) Each switch shall be maintained so that the outer edge of the wheel tread cannot contact the gage side of the stock rail.
(d) The heel of each switch rail shall be secure and the bolts in each heel shall be kept tight.
(e) Each switch stand and connecting rod shall be securely fastened and operable without excessive lost motion.
(f) Each throw lever shall be maintained so that it cannot be operated with the lock or keeper in place.
(g) Each switch position indicator shall be clearly visible at all times.
(h) Unusually chipped or worn switch points shall be repaired or replaced. Metal flow shall be removed to insure proper closure.
(i) Tongue & Plain Mate switches, which by design exceed Class 1 and excepted track maximum gage limits, are permitted in Class 1 and excepted track.

49 C.F.R. §213.135