Metrolinx is writing off $504 million it spent upgrading signalling in the Union Rail Corridor, after changes to its GO Expansion plans made much of the work redundant.

The writeoff was disclosed in the provincial transit agency's annual report, Global News reported. The signalling work, which began in 2013, was meant to modernize the stretch of track that feeds downtown Toronto's Union Station, the hub at the centre of the GO commuter network for riders across the Greater Toronto Area.

Work paused in 2023 over incompatibility risk

The project was halted in 2023 after Metrolinx identified a risk that the upgrades would not fit with the track layouts being developed for GO Expansion.

"The project was paused in 2023 when the risk of incompatibility was identified and while advanced layouts for the tracks were still being developed," the annual report stated.

"Therefore, there was material uncertainty in prior years as to which specific assets would no longer have permanent service potential as this was dependent on the advancement of the GO Expansion track design," the report continued.

By 2026, the report said, Metrolinx had a clearer picture of how the GO network would grow and concluded that large portions of the earlier signalling work would serve no purpose going forward. A usable portion of the completed work will be folded into the new expansion plans.

"Fundamentally changed" plans for the GO network

In a statement, a Metrolinx spokesperson said the pace of GO Expansion has reshaped how the agency intends to run the system.

"The rapid progress of GO Expansion has fundamentally changed how Metrolinx plans to operate the GO Network going forward," the spokesperson wrote.

"As planning advanced for the broader GO Expansion plans, it became clear that the approach to modernizing the legacy signalling system would not support the signalling requirements for the higher-frequency, two-way, all-day service in the most important corridors of the GO Network."

Years of upheaval at the agency

The promise of two-way, all-day GO service across Toronto and the surrounding region has shifted repeatedly in recent years. In January 2024, Metrolinx accepted a proposal from ONXpress — a partnership of German rail operator Deutsche Bahn and Aecon Concessions — to plan and operate the system, with operations set to begin in January 2025 under a 23-year contract.

Deutsche Bahn and Aecon Concessions parted ways with Metrolinx only months after they were scheduled to take over GO operations.

Metrolinx CEO Michael Lindsay, appointed last year, has steered the agency away from reliance on consultants and toward full-time staff. He has also overseen more frequent closures across the network, construction he says is necessary to deliver the more regular train service commuters have been promised.

According to the annual report, the $504-million writeoff amounts to roughly one per cent of Metrolinx's capital asset balance.