49 CFR § 238.707 - Override protection.
---
identifier: "/us/cfr/t49/s238.707"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "49 CFR § 238.707 - Override protection."
title_number: 49
title_name: "Transportation"
section_number: "238.707"
section_name: "Override protection."
chapter_name: "FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION"
part_number: "238"
part_name: "PASSENGER EQUIPMENT SAFETY STANDARDS"
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. 20103, 20107, 20133, 20141, 20302-20303, 20306, 20701-20702, 21301-21302, 21304; 28 U.S.C. 2461 note; and 49 CFR 1.89."
regulatory_source: "64 FR 25660, May 12, 1999, unless otherwise noted."
cfr_part: "238"
---
# 238.707 Override protection.
(a) *Colliding equipment.* (1) Using the dynamic collision scenario described in § 238.705(a), anti-climbing performance shall be evaluated for each of the following sets of initial conditions:
(i) All vehicles in the initially-moving trainset and initially-standing train consists are positioned at their nominal running heights;
(ii) The lead vehicle of the initially-moving trainset shall be perturbed laterally and vertically upwards by 3 inches at the colliding interface; and
(iii) The lead vehicle of the initially-moving trainset shall be perturbed laterally and vertically downwards by 3 inches at the colliding interface.
(2) For each set of initial conditions specified in paragraph (a)(1) of this section, compliance with the following conditions shall be demonstrated after a dynamic impact:
(i) The relative difference in elevation between the underframes of the colliding equipment in the initially-moving trainset and initially-standing train consists shall not change by more than 4 inches; and
(ii) The tread of any wheel of the first vehicle of the initially-moving trainset shall not rise above the top of the rail by more than 4 inches
(b) *Connected equipment override.* (1) Using the dynamic collision scenario described in § 238.705(a), anti-climbing performance shall be evaluated for each of the following sets of initial conditions:
(i) All vehicles in the initially-moving trainset and initially-standing train consists are positioned at their nominal running heights;
(ii) One vehicle is perturbed laterally and vertically upwards by 2 inches, relative to the adjacent vehicle, at the first vehicle-to-vehicle interface in the initially-moving trainset; and,
(iii) One vehicle is perturbed laterally and vertically downwards by 2 inches, relative to the adjacent vehicle, at the first vehicle-to-vehicle interface in the initially-moving trainset.
(2) For each set of initial conditions specified in paragraph (b)(1) of this section, compliance with the following conditions shall be demonstrated after a dynamic impact:
(i) The relative difference in elevation between the underframes of the connected equipment in the initially-moving trainset shall not change by more than 4 inches; and
(ii) The tread of any wheel of the initially-moving trainset shall not rise above the top of rail by more than 4 inches.