USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Office Safety Checker for Moving Block Train Control Systems

Document Series
Technical Reports
Federal Railroad Administration
Report Number
Subject Train Control
Office Safety Checker (OSC), Quasi-moving block (QMB), Full Moving Block (FMB), Interoperable Train Control (ITC), Positive Train Control (PTC), Centralized Interlocking (CIXL)

As part of a project sponsored by FRA, TTCI developed and analyzed a concept for the Office Safety Checker (OSC) component of the Moving Block Office (MBO), a segment of a moving block train control system concept. The OSC component performs a safety validation of MBO safety-critical functions and certain Positive Train Control Back Office Server (PTC-BOS) safety-critical functions. It also leverages on the Quasi-Moving Block (QMB) Operational Concept and the Overlay Positive Train Control (O-PTC) concepts.

DOT is committed to ensuring that information is available in appropriate alternative formats to meet the requirements of persons who have a disability. If you require an alternative version of files provided on this page, please contact
Last updated: Friday, September 15, 2023