[Code of Federal Regulations]
[Title 49, Volume 4]
[Revised as of October 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR236.51]

[Page 642-643]
 
                        TITLE 49--TRANSPORTATION
 
       CHAPTER II--FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF 
                             TRANSPORTATION
 
PART 236_RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION, 
 
              Subpart A_Rules and Instructions: All Systems
 
Sec.  236.51  Track circuit requirements.

    Track relay controlling home signals shall be in deenergized 
position, or device that functions as a track relay controlling home 
signals shall be in its most restrictive state, and the track circuit of 
an automatic train stop, train control, or cab signal system shall be 
deenergized in the rear of the point where any of the following 
conditions exist:
    (a) When a rail is broken or a rail or switch-frog is removed except 
when a rail is broken or removed in the shunt fouling circuit of a 
turnout or crossover, provided, however, that shunt fouling circuit may 
not be used in a turnout through which permissible

[[Page 643]]

speed is greater than 45 miles per hour. It shall not be a violation of 
this requirement if a track circuit is energized:
    (1) When a break occurs between the end of rail and track circuit 
connector; within the limits of rail-joint bond, appliance or other 
protective device, which provides a bypath for the electric current, or
    (2) As result of leakage current or foreign current in the rear of a 
point where a break occurs.
    (b) When a train, locomotive, or car occupies any part of a track 
circuit, including fouling section of turnout except turnouts of hand-
operated main track crossover. It shall not be a violation of this 
requirement where the presence of sand, rust, dirt, grease, or other 
foreign matter prevents effective shunting, except that where such 
conditions are known to exist adequate measures to safeguard train 
operation must be taken.
    (c) Where switch shunting circuit is used:
    (1) Switch point is not closed in normal position.
    (2) A switch is not locked where facing-point lock with circuit 
controller is used.
    (3) An independently operated fouling-point derail equipped with 
switch circuit controller is not in derailing position.

[33 FR 19684, Dec. 25, 1968, as amended at 49 FR 3383, Jan. 26, 1984]