Automatic train control
The first experimental apparatus was installed on the Henley branch line in January 1906 by the Great Western Railway,[1][2] although it would now be referred to as an automatic warning system (AWS) because the driver retained full command of braking.
[citation needed] In 2017, Huawei was contracted to install GSM-R partly to provide communication services to automatic train protection systems.
Second, the brakes are applied when the train achieves maximum speed, meaning reduced ride comfort.
Third, if the operator wants to run faster trains on the line, all the related relevant wayside and on-board equipment must be changed first.
All this data forms the basis for ATC decisions when controlling the service brakes and stopping the train.
In consequence of the Sorø railway accident, which occurred in April 1988, the new system was progressively installed on all Danish main lines from the early 1990s onwards.
ATC was first trialled in Norway in 1979, after the Tretten train disaster, caused by a signal passed at danger (SPAD), occurred four years earlier.
This rail sloped at each end and was known as an ATC ramp and would make contact with a shoe on the underside of the passing locomotive.
The ramp would lift the shoe on the passing locomotive and start a timer sequence at the same time sounding a horn on the footplate.
Starting in 2017, the Toronto Transit Commission began the implementation of ATC on to Line 1 Yonge–University, at a cost of $562.3 million.
ATC was introduced in phases, beginning with a test on 4 November 2017 during regular service between Dupont and Yorkdale stations.
It was first introduced in a permanent manner with the opening of the Toronto–York Spadina subway extension on 17 December 2017, between Vaughan and Sheppard West stations.
[15][16] Implementation of the system on to the remainder of the line was carried out during weekend closures and night time work when the subway would close.
[16] Converting all of Line 1 to ATC required the installation of 2,000 beacons, 256 signals, and more than one million feet of cable.
The ATC comes from electronics in the locomotive that implement some form of speed control based on the inputs of the cab signalling system.
[20] Due to the more sensitive handling and control issues with North American freight trains, ATC is almost exclusively applied to passenger locomotives in both inter-city and commuter service with freight trains making use of cab signals without speed control.
Some high-volume passenger railroads such as Amtrak, Metro North and the Long Island Rail Road require the use of speed control on freight trains that run on all or part of their systems.
[20] While cab signalling and speed control technology has existed since the 1920s, adoption of ATC only became an issue after a number of serious accidents several decades later.
Only three freight railroads, Union Pacific, Florida East Coast and CSX Transportation, have adopted any form of ATC on their own networks.
Union Pacific's was inherited on portions of the Chicago and Northwestern east–west main line and works in conjunction with an early two aspect cab signaling system designed for use with ATC.
