GO Transit train yard with train coming towards camera from afar, trains flanking on adjacent tracks; GO Transit train yard with train coming towards camera from afar, trains flanking on adjacent tracks;

GO Expansion – On-Corridor Works (OnCorr), Toronto, ON

Transforming transit in one of the largest metropolitan areas in North America

The Greater Toronto and Hamilton Region is experiencing incredible growth, with an estimated 12 million people calling the region home by 2041. GO Transit — the regional commuter system for the Greater Toronto and Hamilton Region — serves one of the largest metropolitan areas in North America. The GO Expansion program will make it easier for customers to get to where they need to go, by creating a network that has the capacity to deliver 15-minute or better, two-way, all-day service on core segments of GO rail lines.

Since 2022, Arup has served as Technical Advisor for the largest rail expansion project ever undertaken by Metrolinx, a transit agency in Ontario, Canada’s most populous province. When complete, the GO Expansion Program is projected to deliver over 600km of electrified track, with a projected ridership of approximately 200 million by 2040 — an increase from 60 million prior to the COVID-19 pandemic. Regional commuter trains will make more than 10,000 weekly trips — up from 3,500 — on an electrified network providing all-day train service in the Greater Toronto and Hamilton Region. Currently, only about one per cent of North America’s rail networks are electrified, in contrast to Europe, where more than 60% of commuter rail lines are electric. The multi-phase project is being delivered through a progressive procurement model between Metrolinx and ONxpress Transportation Partners (ONxpress).

An Arup-led team, including subconsultants AECOM, Egis, and Network Rail Consulting, is supporting Metrolinx to map out and deliver this transformation. Services include technical reviews of design packages, BIM and data strategy, system safety and assurance, project management support, digital analytics and reporting, strategic advice related to in-cab signalling and electric locomotives as well as managing the design and construction of strategic logistics hubs.

Project Summary


600km of electrified track and 205 km of new track

10,000+ weekly regional commuter services across the network — up from 3,500

OnCorr: The final and most critical component of the GO Expansion program

The GO Expansion – On-Corridor Works (OnCorr) project includes all works that will unlock faster, more frequent train service, such as track, signalling, electrification, and a new and modified fleet. In December 2023, Metrolinx accepted ONxpress’ proposal for the operations and maintenance of the GO Transit system beginning January 1, 2025. It is the largest capital infrastructure project in the GO Expansion program and must integrate its work with new and existing stations, corridors, and facilities to ensure the system runs more and better service. Key aspects include:

  • Operating and maintaining GO Trains

  • Train service planning

  • Introducing electrification and ETCS digital signalling system

  • Maintenance services for new assets, such as electrification and signalling 

  • Improving Union Station at track level

  • Civil and track investments across the network

  • Compliance with Metrolinx safety, security, and emergency management policies

OnCorr provides a real opportunity for us to leverage our international systems engineering expertise especially in European Train Control System, rolling stock and electrification to support the delivery of this historic program for Metrolinx. It also represents a significant opportunity to apply our worldwide expertise to the Americas market. ” Peter Guest Peter Guest Principal

Ensuring uninterrupted service

Over the coming years, work will be delivered in phases while Metrolinx continues to provide GO train service for its customers. Offering faster, more frequent service across the Greater Toronto and Hamilton Area requires large-scale planning and design to determine many design and construction details prior to major construction beginning. Metrolinx has appointed a consortium comprising Alstom, Aecon, FCC and Deutche Bahn, known collectively as ONxpress, to deliver the program.