49 CFR § 236.339 - Mechanical locking, maintenance requirements.

---
identifier: "/us/cfr/t49/s236.339"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "49 CFR § 236.339 - Mechanical locking, maintenance requirements."
title_number: 49
title_name: "Transportation"
section_number: "236.339"
section_name: "Mechanical locking, maintenance requirements."
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"
---


# 236.339 Mechanical locking, maintenance requirements.

Locking and connections shall be maintained so that, when a lever or latch is mechanically locked the following will be prevented:

(a) *Mechanical machine*—(1) *Latch-operated locking.* Raising lever latch block so that bottom thereof is within three-eighths inch of top of quadrant.

(2) *Lever-operated locking.* Moving lever latch block more than three-eighths inch on top of quadrant.

(b) *Electromechanical machine*—(1) *Lever moving in horizontal plant.* Moving lever more than five-sixteenths inch when in normal position or more than nine-sixteenths inch when in reverse position.

(2) *Lever moving in arc.* Moving lever more than 5 degrees.

(c) *Power machine*—(1) *Latch-operated locking.* Raising lever latch block to that bottom thereof is within seven thirty-seconds inch of top of quadrant.

(2) *Lever moving in horizontal plane.* Moving lever more than five-sixteenths inch when in normal position or more than nine-sixteenths inch when in reverse position.

(3) *Lever moving in arc.* Moving lever more than 5 degrees.