Federal Railroad Administration, DOT § 236.504 RULES AND INSTRUCTIONS individual carrier where automatic train control systems now in service enforce speed § 236.426 Interlocking rules and in- restrictions higher than those required by structions applicable to traffic con- definitions in §§ 236.700 to 236.838 inclusive. trol systems. (3) Maximum-speed restriction, ef- The rules and instructions prescribed fecting an automatic brake application in §§ 236.327 and 236.328, § 236.330 to whenever the predetermined maximum § 236.334, inclusive, and § 236.342 shall speed limit is exceeded. apply to traffic control systems. INSPECTION AND TESTS § 236.502 Automatic brake application, initiation by restrictive block condi- § 236.476 Interlocking inspections and tions stopping distance in advance. tests applicable to traffic control An automatic train-stop or train- systems. control system shall operate to initiate The inspections and tests prescribed an automatic brake application at in §§ 236.377 to 236.380, inclusive, and least stopping distance from the en- §§ 236.382, 236.383, and 236.386 shall apply trance to a block, wherein any condi- to traffic control systems. tion described in § 236.205 obtains, and [49 FR 3386, Jan. 26, 1984] at each main track signal requiring a reduction in speed. Subpart E—Automatic Train Stop, § 236.503 Automatic brake application; Train Control and Cab Signal initiation when predetermined rate Systems of speed exceeded. STANDARDS An automatic train control system shall operate to initiate an automatic § 236.501 Forestalling device and brake application when the speed of speed control. the train exceeds the predetermined (a) An automatic train stop system rate as required by the setting of the may include a device by means of speed control mechanism. which the automatic application of the brakes can be forestalled. § 236.504 Operation interconnected (b) Automatic train control system with automatic block-signal system. shall include one or more of the fol- (a) A continuous inductive automatic lowing features: train stop or train control system shall (1) Low-speed restriction, requiring operate in connection with an auto- the train to proceed under slow speed matic block signal system and shall be after it has either been stopped by an automatic application of the brakes, or so interconnected with the signal sys- under control of the engineman, its tem as to perform its intended function speed has been reduced to slow speed, in event of failure of the engineer to until the apparatus is automatically acknowledge or obey a restrictive way- restored to normal because the condi- side signal or a more restrictive cab tion which caused the restriction no signal. longer affects the movement of the (b) An intermittent inductive auto- train. matic train stop system shall operate (2) Medium-speed restriction, requir- in connection with an automatic block ing the train to proceed under medium signal system and shall be so inter- speed after passing a signal displaying connected with the signal system that an approach aspect or when approach- the failure of the engineer to acknowl- ing a signal requiring a stop, or a stop edge a restrictive wayside signal will indication point, in order to prevent an cause the intermittent inductive auto- automatic application of the brakes. matic train stop system to perform its NOTE: Relief from the requirements of intended function. paragraphs (b) (1) and (2) of this section will be granted, insofar as speed limits fixed by [49 FR 3386, Jan. 26, 1984] definitions of Slow and Medium speeds are concerned, upon an adequate showing by an 703 VerDate Mar<15>2010 14:14 Nov 15, 2011 Jkt 223217 PO 00000 Frm 00713 Fmt 8010 Sfmt 8010 Q:\49\49V4.TXT ofr150 PsN: PC150.