which stands for Untergrundbahn ("underground rail"). Many systems in East, Southeast and South Asia like Taipei, Chennai and Singapore, are called "MRT", which stands for "mass rapid transit". Systems that are predominantly elevated may be referred to as "L", as in Chicago, or "Skytrain", as in Bangkok and Vancouver. Other less common names include "T-bane", which stands for "tunnelbana" (in Scandinavia, literally tunnel track) and "MTR" (mass transit railway). Monorail A monorail is a railway in which the track consists of a single rail, as opposed to the traditional track with two parallel rails. Commuter rail A commuter rail, regional rail or suburban rail system operates on mainline trackage, which may be shared with intercity rail and freight trains. Systems tend to operate at lower frequencies than rapid transit or light rail systems but tend to travel at higher speeds, have more widely spaced stations and cover longer overall distances. They have high passenger capacities per single train. Though many European and East Asian commuter rail systems operate with frequencies and rolling stock similar to that of rapid transit, they do not qualify as such because they share tracks with intercity/freight trains, or they have at grade crossings. For example, S-trains are hybrid systems combining the characteristics of both rapid transit and commuter rail systems. Generally, S-trains share tracks with mainline passenger and freight trains, but the distances between stations and the service headway resemble metro systems. AGT Automated Guideway Transit systems tend to operate with medium passenger capacities. Funicular A funicular is a cable-driven inclined railway that uses the weight of descending cars to help pull the ascending cars up the slope. Cable car A cable car, in the context of mass transit, is a system using rail cars that are hauled by a continuously-moving cable that runs at a constant speed. Individual cars stop and start by releasing and gripping the cable as required. Cable cars are distinct from funiculars (whose cars are permanently attached to the cable) and cable railways (which are similar to funiculars but have rail vehicles that are attached and detached manually). Classification issues Transit agencies' names for lines do not necessarily reflect their technical categorization. For example, the Green Line in Boston is referred to as a subway although it is mostly made up of above-ground portions. Conversely, the Docklands Light Railway in London, C Line in Los Angeles, and some metro lines