Shatabdi Express trains are a series of fast (called superfast in India) passenger trains operated by Indian Railways to connect Metro cities with other cities important for tourism, pilgrimage or business. Shatabdi Express are day-trains and they return to the station of origin the same day.
The Shatabdis are among the fastest trains in India and the Indian Railways considers them as prestigious. The Shatabdi Express trains run over short to medium distances while the Rajdhani Expresses are long-distance trains connecting the nation's capital New Delhi to capitals of states. Both series of trains have a regular speed of about 130 km/h (81 mph). The 12001 Bhopal Shatabdi express, however, runs at a peak speed of 150 km/h (93 mph), which makes...
more... it the fastest train in India.
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The Jan Shatabdi Express is a more affordable variety of the Shatabdi Express, which has both AC and non-AC accommodation. The word 'Jan' refers to common people.
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Source- Wikipedia