---
kind: "section"
citation: "49 C.F.R. § 238.707"
title: "49"
number: "238.707"
heading: "Override protection."
url: "https://uscodex.org/cfr/49/238.707"
---

# §238.707. Override protection.

- (a) **Colliding equipment.**
  - (1) Using the dynamic collision scenario described in [§ 238.705(a)](/cfr/49/238.705.md?p=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)](#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)](/cfr/49/238.705.md?p=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)](#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.

## Notes

### Source

Source: 83 FR 59219, Nov. 21, 2018, unless otherwise noted.

### Authority

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.

### Source

Source: 64 FR 25660, May 12, 1999, unless otherwise noted.