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

Centralized Interlocking (CIXL) for Moving Block Research Project

Document Series:
Research Results
Author:
  • Federal Railroad Administration
Report Number
RR 21-07
Office
RDI-23
Subject:
Positive Train Control
Keywords:
Centralized interlocking system, CIXL, Quasi-Moving Block, QMB, Positive Train Control, PTC, Communications-Based Train Control, CBTC, control point, CP, Wayside Status Messages, WSM, railroad, train control
Report Number
RR 21-07
Office
RDI-23
Document
CIXL Moving Block Research.pdf (463.86 KB)

From September 9, 2019, to March 8, 2021, the Federal Railroad Administration (FRA) sponsored Transportation Technology Center, Inc. (TTCI), to develop and analyze a concept for a centralized interlocking (CIXL) system that supports moving block methods of train control, improves overall availability and maintainability, and satisfies the needs of North American railroads.


Last updated: Wednesday, August 20, 2025