RAIL-BASED TRANSIT SYSTEMS
In contrast to urban growth in industrialized countries, the growth of few Third World cities was based on tracked transport. Nevertheless, mounting road-traffic problems in large Third World cities have encouraged transport planners to consider rail-based transit systems. There include conventional tram or streetcar systems, light rail units running along existing streets, rapid-rail units using a segregated track, and suburban rail or metro-type units, possibly sharing track with inter-city trains.
The capital and operating costs of different rail systems very and will be influenced by local conditions (such as the existing urban fabric, terrain and route network) and the efficiency with which the system is managed. In general, however, because of their high costs, rail transits can provide only their high costs, rail transits can provide only restricted spatial coverage of the city, and most have