Mumbai's 12 km metro opened officially in June 2014. Work on two new lines began in October 2015. Line 2 will be 18.5 km with 17 stations. Line 3, actually an extension of Line 2, will be 16.5 km long. Both lines will be completely underground.
Also approved is Line 4, a 32 km line with 24 underground stations and 6 elevated stations. Line 4 will connect commuters with the monorail.
Several systems were in the planning stages for this city on an island off the west coast of India. One plan called for a 17.5 km, 20 station subway between Bandra and Colaba. Another called for an elevated line between Bandra and Kurla. A once promising one was the home grown Sky Bus, a made in India monorail, with three lines.
In May 3003, an elevated 10 km LRT was to be built between Andheri and Ghatkopar via Asalpha, Marol, Chakala and Saki Naka. The SkyBus was rejected because the technology of a vehicle running over air is yet unproven. Described as "not for for mass transport", it is reminiscent of the way your bank will only loan you money only when you don't really need it.
In January 2004,
transit plan, including a 146 kilometer metro, was unveiled by the
Mumbai Metropolitan Region Development Authority (MMRDA).
Included was 32 km of subway. In June of the same year (2004 for those of you with poor shoirt term memory), the government approved a 13 station elevated
light rail line between Ghatkopar and Versova. The line wass expected to
open in 2008. It would be mostly elevated, except a short stretch
underground where it crossed the Western Express Highway. A short spur would
also connect with Mumbai's international airport.
Official Home Page
Railway Technology Page
Mumbai Metro Region Development Autjority page on the Metro
MRT page from Metroplanet
Mumbai Railway home page
MRT station photos
Skytrain LRTS for Bombay
Transportation in Mumbai