Railroad Rules, Signalling, Operations:

North American Signaling

by Carsten S. Lundsten.

Milwaukee Road single track Automatic Block Signaling (original electrification) document added January 14, 2020
AT&SF single track "Overlap" Automatic Block Signaling (original version from the 1920s) document added April 5, 2020

North American Signaling documents

     Basics of North American Signaling and Safety principles
     Basic principles of Automatic Block Signaling, Interlocking, Traffic Control Systems and Centralized Traffic Control

Track Occupancy Control Systems
     Track Warrant Control (TWC)
     Direct Traffic Control (DTC)

Automatic Block Signaling systems
     Southern Pacific single track Automatic Block Signaling
            Simulator for SP-style ABS on the Central Oregon & Pacific
     Absolute Permissive Block signaling
            Pennsylvania RailRoad Absolute Permissive Block Signaling
            Illinois Central Cab Signal based Absolute Permissive Block Signaling
     AT&SF double track Automatic Block Signaling
     AT&SF "Overlap" single track Automatic Block Signaling, original (1920s) version - new April 5, 2020
     AT&SF "Flat Pair" single track Automatic Block Signaling
     Chicago, Milwaukee & St. Paul Railroad (later the Milwaukee Road) single track Automatic Block Signaling on electrified lines, original installation - new January 14, 2020

Centralized Traffic Control systems
     Pittsburgh & West Virginia "Poor Man's CTC"

Signal Aspects and Indications
      Atchison, Topeka and Santa Fe, 1995
      Bessemer & Lake Erie Railroad, 1957
      Kansas City Southern, 1998
      Pittsburgh & West Virginia, 1953
      Southern Pacific, 1996
      Union Pacific, 1988
      Western Maryland, 1973

Comments, corrections and more information is very welcome. Please use this contact form


Text, Images except for wallpaper, HTML: Carsten S. Lundsten.
Wallpaper photo: Kindly by Eric Schmelz, modified by Carsten S. Lundsten