CTrain is a light rail system in Calgary, Alberta, Canada. Much of the system functions as a high-capacity light metro, while in the downtown free-fare zone, trains run like a modern tram with a dedicated right-of-way. This subway-surface alignment is known as semi-metro.

Light rail transit (LRT) is a form of passenger urban rail transit characterized by a combination of tram and rapid transit features. While its rolling stock is similar to that of a traditional tram, it operates at a higher capacity and speed and often on an exclusive right-of-way. In many cities, light rail transit systems more closely resemble, and are therefore indistinguishable from, traditional underground or at-grade subways and heavy-rail metros.