Light Rail Transit (LRT)
Light Rail Transit is also known by the name train. LRT can be run on the surface if road space is available (as in Kolkata) or as elevated, with pillars located in the median of roads. It can carry upto 20,000 persons per hour per direction.
Rapid Rail Transit (Metro Rail)
Rapid Rail Transit systems, also called Metro Rail systems, can carry 60,000 persons per hour per direction. They can be surface, elevated or underground. The Metro Rail of Delhi is a good example. The Kolkata Metro, 16.4 Km long, has cost about Rs. 1,000 crores (cost at 1980-90). At current prices, the system may cost about Rs. 100-200 crores per Km.