Line 1 Automatic Train Control


When the original Yonge Line, from Eglinton to Union, opened in 1954, it was equipped with a fixed-block signal system. A fixed block signal system divides the subway line into geographical blocks. Only one train at a time is allowed in each block, while the adjacent blocks provide a buffer zone. This system remains safe for operations. However, its reliability is diminishing. A new signalling system is necessary to safely run more trains, accommodate increased ridership demand and provide more reliable customer service.

Resignalling Line 1 with Automatic Train Control (ATC) will improve reliability and capacity on Canada’s busiest subway system. ATC provides the benefit of real-time central train control with precise train location. With ATC, train speed and separation between trains is controlled automatically through a moving-block system versus the outdated fixed-block system.


Some of the benefits that the ATC upgrades will bring to Line 1 and our riders include:

Increased safety

  • Train speed and distance between trains are controlled automatically rather than being human controlled.
  • Real-time central train control with precise train location data.

Travel Time Improvements

  • Trains are operated automatically to optimize speed and reduce travel
  • 80% Reduction in Signal Delays (Dupont to Wilson)
  • Travel time consistent every run.

Lower Operating Costs

Train electricity usage will become much more efficient.

What we’re doing

Resignalling of Line 1 with ATC includes the design, installation, testing and commissioning of new signalling equipment from Alstom Signalling. An upgrade to the Centralized Signalling System (CSS) is required to integrate the new ATC system. It also includes new ATC train-borne equipment on the Line 1 Toronto Rocket (TR) fleet and subway work cars.

The ATC system is complex, and the installation, testing and commissioning activities can only be performed efficiently when trains are not operating, such as overnight or during scheduled subway closures.

During subway closures, crews typically install new cables, trackside signalling equipment or special track work in the tunnels. This work is labour intensive and can’t all occur during the regular maintenance window each night when subway service ends, though work does continue in those areas each night. Each single day closure is the equivalent of about five weeks of nightly work.

To date, eleven subway work cars are equipped with Automatic Train Protection (ATP). ATP has resulted in improved maintenance windows for track maintenance activities in the segment of Line 1 operating in ATC.

The TTC is installing a state-of-the-art signal system

Critical subway infrastructure, such as signal systems, tunnel structures or track beds, requires constant maintenance and, after more than half a century of service in some cases, full replacement. When complete, the subway system will be more reliable, efficient and provide greater capacity for the TTC’s 1.7 million daily riders.

Next steps

The TTC appreciates and thanks all of its customers, businesses and the public-at-large for their patience and understanding as this work progresses. Weekend and early evening subway closures continue to be required to keep the last phases of the ATC project on track. See the latest schedule for weekend subway closures.

The entirety of Line 1 is planned to have ATC completed by Q3 2022.

Background Reports

City Council Reports

TTC’s 2019-2028 Capital Budget (March 7, 2019)

TTC Board Reports

Automatic Train Control Alstom Contract Amendment(s) (January 27, 2020)

Automatic Train Control Re-Baselining and Transit Systems Engineering Review (April 11, 2019)

Financial Update for the Period Ended September 29, 2018 (January 24, 2019)

TTC 15-Year Capital Investment Plan and 2019-2028 Capital Budget and Plan (January 24, 2019)

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