O-Train South Extension

Connecting people and places with thoughtfully designed public transportation makes it easier to lighten our collective carbon footprint. That goal lies at the heart of our work on the O-Train South Extension.

Big idea

The O-Train South Extension is part of the Stage 2 O-Train Expansion project, which includes three major expansions to Ottawa’s O-Train network. This project aims to provide residents and visitors with accessible, affordable and frequent public transit access throughout the city. Segments of the O-Train South Extension have been used for different railways since 1854. The original O-Train opened in 2001 and began as a pilot project. Formerly known as the Trillium Line and now named O-Train Line 2, it ran between Bayview Station in the north and Greenboro Station in the south. To connect more communities and create first-time rail access to the airport, the line was extended further south.

In 2019, TransitNEXT, a wholly owned subsidiary of AtkinsRéalis, was awarded the end-to-end delivery of the Stage 2 South Extension, including engineering, construction, and 27 years of maintenance and rehabilitation of the entire system. This extension reaches Limebank Station in Riverside South and includes the creation of the Airport Link (Line 4), connecting South Keys Station to Ottawa International Airport.

Our end-to-end capability

The project focused on two major areas: the redesign and rebuild of the existing line, and the south extension of the line.

The redesign and rebuild of the existing line apply to its tracks and five stations, plus adding two new stations at Corso Italia and Walkley in the process. We lengthened legacy station footprints to accommodate longer trainsets and added new stations to support the City of Ottawa’s goal for greater capacity and a more connected transit experience. The project also included the widening existing passing tracks, which required careful widening of the existing rock trench in the centre of the city.

In addition, Line 2 was extended further south with eight new stations and an additional 15.5 kilometres of rail, of which a significant portion is double tracked. A new LEED-Certified Maintenance and Storage Facility (MSF) is the heart of the system. It comprises three new buildings: a sanding and inspection facility, a train wash, and a state-of-the-art main building. Equipped with light and heavy maintenance bays, a wheel lathe, a warehouse, train jacks and overhead cranes, this facility is where the long-term maintenance of the train fleet happens each night. The new MSF was built with live operations, train assembly and train testing happening simultaneously.

One of the biggest highlights of the O-Train’s south extension is a 4.2-kilometre link to the Ottawa International Airport. A newly built elevated guideway connects passengers directly to domestic and international check-in counters for seamless transitions. Peak service will see trains arriving every 12 minutes, making this a reliable option for travellers.

All combined, the work included 15 bridges: 13 new bridges and two bridge rehabilitations. In total, the project required 33.8 kilometres of track and a new signalling and train control system.

Upgrading and preserving historic elements

The project scope included significant upgrades and renovation to three key elements along the line.

First was the Dow's Lake Tunnel, completed in 1965 which was redesigned and upgraded in accordance with new National Fire Protection Association standards. We also added cellular connectivity to bring the tunnel into the 21st century. Second was the Ellwood Diamond rail bridge, one of the 17 bridges designed and constructed or rehabilitated as part of the South Extension project. This newly elevated rail crossing allows Line 2 trains to travel above the VIA Rail tracks, creating dedicated guideways for each and eliminating the shared at-grade crossing, which speeds up service and improves safety. Third was the Rideau River rail bridge, first constructed in 1871. As part of a significant refurbishment, our team remediated the steel superstructure and piers and replaced over 5,000 rivets, extending the lifespan of this historic bridge for another 50 years.

All-weather trains

AtkinsRéalis procured seven FLIRT trains for the O-Train South Extension project. Manufactured in Switzerland by Stadler, these 81-metre, 178-ton trains deliver 1,920 kW of power and are designed for Ottawa’s extreme temperatures. With a capacity of 420 passengers, they offer double the capacity of the previous trains. We also upgraded the former fleet of Alstom LINT trains with new CCTV systems, train signaling infrastructure, rebuilt the powerpacks where diesel is converted to electrical power and replaced mechanical components. These 262-passenger trains will operate on Line 4 (Airport Link) or be coupled for mainline use, providing maximum operational flexibility.

Full circle: The ecological connection

We are proud to support the City of Ottawa in its mission to help residents reduce their reliance on cars. Additionally, various environmental strategies have been implemented to reconnect green spaces on both sides of the tracks. These include the installation of culverts, rail underpasses, and an ecological bridge at High Road, designed to enable the safe passage of small and large animals while preserving habitat connectivity.