49 CFR § 236.503 - Automatic brake application; initiation when predetermined rate of speed exceeded.

---
identifier: "/us/cfr/t49/s236.503"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "49 CFR § 236.503 - Automatic brake application; initiation when predetermined rate of speed exceeded."
title_number: 49
title_name: "Transportation"
section_number: "236.503"
section_name: "Automatic brake application; initiation when predetermined rate of speed exceeded."
chapter_name: "FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
part_number: "236"
part_name: "RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "49 U.S.C. 20102-20103, 20107, 20133, 20141, 20157, 20301-20303, 20306, 20501-20505, 20701-20703, 21301-21302, 21304; 28 U.S.C. 2461 note; and 49 CFR 1.89."
regulatory_source: "33 FR 19684, Dec. 25, 1968, unless otherwise noted."
cfr_part: "236"
---


# 236.503 Automatic brake application; initiation when predetermined rate of speed exceeded.

An automatic train control system shall operate to initiate an automatic brake application when the speed of the train exceeds the predetermined rate as required by the setting of the speed control mechanism.