There are two types of mass rapid transit systems in the Taipei metropolitan area – heavy rail rapid transit and automated guideway transit. Brief descriptions of these systems follow.
1. Heavy Rail Rapid Transit (RRT): Trains travel on an electric railway with the capacity for a heavy volume of traffic. Distinguishing features include long electric multiple unit (EMU) trains, usually powered by a third rail, high-platform stations, fare collection at stations and not on trains, and frequent service. RRT is characterized by high-speed and rapid-acceleration EMU rail cars operating on fixed rails. It is capable of carrying at least 50,000 passengers per hour in each direction. Heavy rail has sophisticated signaling and high-platform loading.
2. Automated Guideway Transit (AGT): Automated guideway transit is a system of guided transit passenger EMU vehicles operating with a fully automated system (no crew). The wheels can be steel or rubber type.