49 CFR § 236.552 - Insulation resistance; requirement.

---
identifier: "/us/cfr/t49/s236.552"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "49 CFR § 236.552 - Insulation resistance; requirement."
title_number: 49
title_name: "Transportation"
section_number: "236.552"
section_name: "Insulation resistance; requirement."
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"
---


# 236.552 Insulation resistance; requirement.

When periodic test prescribed in § 236.588 is performed, insulation resistance between wiring and ground of continuous inductive automatic cab signal system, automatic train control system, or automatic train stop system shall be not less than one megohm, and that of an intermittent inductive automatic train stop system, not less than 250,000 ohms. Insulation resistance values between periodic tests shall be not less than 250,000 ohms for a continuous inductive automatic cab signal system, automatic train control system, or automatic train stop system, and 20,000 ohms for an intermittent inductive automatic train stop system.

[49 FR 3387, Jan. 26, 1984]