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

I-ETMS™ Positive Train Control Passenger Braking Algorithm Enhancement – Phase II

Document Series
Technical Reports
Federal Railroad Administration
Report Number
Subject Positive Train Control
Positive Train Control, PTC, braking, braking algorithm enhancements, field testing, Electric Multiple Unit, EMU, Diesel Multiple Unit, DMU, enforcement algorithm, enforcement algorithms, EA
PTC Braking EA.pdf (3.81 MB)

The Federal Railroad Administration (FRA) funded Transportation Technology Center, Inc. (TTCI) to examine the performance benefits of four potential modifications to the current methodology used for passenger braking enforcement algorithms (EA) in the Interoperable Electronic Train Management System (I-ETMS™) Positive Train Control (PTC). Additionally, researchers developed a methodology for simulating PTC braking algorithm performance for Electric Multiple Unit/Diesel Multiple Unit consists. This process does not rely on brake pipe pressure changes and requires different information to be provided to the EA and simulation program. Finally, the project included field testing to demonstrate the modifications to the EA reflected operational data. Due to the global pandemic, equipment was limited and testing was conducted using available cars and locomotives. The testing was conducted using the baseline, Total Approach Management, tuned train type, and specified consist algorithms. An analysis of the test results showed that the enhancements could be used to improve the EA performance for certain scenarios.

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 29, 2023