Union Pearson Express

The Union Pearson Express (UP Express or simply UP) is an airport rail link connecting Union Station in Downtown Toronto to Toronto Pearson International Airport. The UP Express began operation on 6 June 2015, in time for the 2015 Pan American Games. The UP Express travels between Union and Pearson in 28 minutes departing every 15 minutes, seven days a week. At the launch announcement, it was stated that the UP Express was projected to carry 2.35 million passengers annually and eliminate approximately 1.2 million car trips in the first year. As of 2019, it carried 4.5 million passengers annually.

UP Express is operated as an independent division of Metrolinx, similarly to GO Transit. An airport rail link was one of the priority projects identified in Metrolinx's regional transportation plan, The Big Move. Construction began in 2011 as part of the Georgetown South Project, which expanded the rail corridor the UP Express shares with GO Transit and Via Rail. UP Express uses diesel multiple unit (DMU) trains that meet United States Environmental Protection Agency Tier 4 emission standards. Metrolinx plans to electrify the UP Express along with the Kitchener line, as well as use a unified train set with the rest of the GO network, although as of 2019, the project was still in its early stages. The UP Express has been criticized for not using electric trains from the outset, and for its initial fare prices that were very high compared with other North American airport–city connections.

The Union Pearson Express' maximum operating speed is 145 km/h (90 mph), and its average speed is 56 km/h (35 mph). The line initially operated with four stations but a fifth was added in November 2025.