The south extension of Ottawa’s light-rail transit system opened in January after a nearly three-year delay. 

During the years of construction, the city not only expanded Line 2 — the Trillium Line of the O-Train — but also added a whole new service: Line 4 to the Ottawa airport. 

The line began service on Jan. 6. The train runs back and forth between the South Keys station and the Macdonald-Cartier International Airport, with a stop at Uplands. 

The route is located entirely in Ward 10, or Gloucester-Southgate. The new trains can carry up to 600 passengers, with 240 seats and standing room for 360 people. 

After a long wait, Ottawa residents and visitors to the capital now have a service that can take them from the airport all the way downtown in less than an hour. 

To do so, riders can take Line 4 from the airport and switch to a Line 2 train at South Keys. They may take this train all the way to Bayview. 

Line 1, or the Confederation Line, also travels through Bayview a short distance from Ottawa’s urban core, giving travelers from the south end access to faster public transit through the city. 

Shot from inside Line 4 of the O-Train. Seats are shown, and the "Airport" sign can be seen through a window.
Inside the O-Train Line 4. [Photo © Amber Gray]

OC Transpo announced that the 97 bus, which goes from the airport to Hurdman Station, would continue to run for a period of time to allow for a smooth transition, until Line 4 service began seven-day service.

The same service was continued for other buses that run parallel with the O-Train, such as bus 2, which runs from Bayview to South Keys. 

At the time of the Line 4 launch, there was optimism about the long-awaited opening of the airport route, but many transit users also expressed doubts about the service because of previous delays and breakdowns. 

In fact, mechanical issues with Line 4 created delays only a week after the grand opening. One train had to be removed from operation for several hours, causing short gaps in service between the South Keys and Airport stations. 

Other expansions in Ottawa’s light-rail system are expected to take place over the next few years. 

Line 1 is scheduled to expand eastward from Blair to Trim Station this year. In 2026, Line 1 should also expand southwest to Algonquin College. As well, Line 3 is set to open in 2027, running from Tunney’s Pasture to Moodie Station in west-end Ottawa.