June 8, 2015

This morning, shortly before the start of subway service, the Toronto Transit Commission experienced a failure of all communications systems – both main and back-up – that led to the suspension of service on the entire subway system for 95 minutes.

The loss of radio communications between subway trains and the TTC’s transit control centre was the safety critical issue that caused the suspension of service, as trains cannot go through tunnels without being able to communicate with the control centre. At the same time, diagnosis and recovery, as well the ability to communicate with customers, was severely impeded by the loss of other communications systems, including email, internet and the TTC’s phone system.

Yesterday evening, the TTC’s Hillcrest complex, which houses the control centre, experienced a power failure that activated the uninterrupted power supply (UPS). A failure within the UPS caused its battery system to drain, preventing power from getting to critical communications systems. An investigation into the UPS malfunction continues. Once that is determined, the TTC can implement remedies, as required, to prevent a recurrence.

The TTC did not use shuttle buses during today’s disruption, as buses are deployed from operating routes. Because there are simply not enough buses to replace an entire subway system, shuttle buses would have decimated the existing bus network and caused further disruption to customers. In fact, the best alternative to the subway this morning was the surface network of buses and streetcars.

Timeline:

5:31 a.m. - Loss of radio communications; all four subway lines halted

7:16 a.m – Line 3 SRT began operating between Lawrence East and McCowan stations

7:32 a.m. – Line 4 Sheppard began normal operation

7:35 a.m. – All subway service back up and running

TTC CEO Andy Byford will be available to speak to media at TTC head office, 1900 Yonge Street (Davisville Station), at approximately 3:30 p.m. today.



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