Candiac is a commuter railway line in Greater Montreal, Quebec, Canada. It is operated by Exo, the organization that operates public transport services across this region.

Exo, officially known as Réseau de transport métropolitain, is a public transport system in Greater Montreal, including the Island of Montreal, Laval, and communities along both the North Shore of the Mille-Îles River and the South Shore of the St. Lawrence River. It was created on June 1, 2017, taking over from the Agence métropolitaine de transport. The RTM operates Montreal's commuter rail and metropolitan bus services, and is the second busiest such system in Canada after Toronto's GO Transit. In May 2018, the former Réseau de transport métropolitain (RTM) was branded as Exo.