The Fairy Queen is a steam locomotive, plying between the Indian capital of New Delhi and Alwar, in Rajasthan. It was certified by the Guinness Book of Records in 1998 as being the world’s oldest one in regular operation after being restored to haul a luxury train in order to boost tourism in Rajasthan.
India’s oldest working locomotive is the Fairy Queen, manufactured in 1855. It is also the oldest functioning steam engine in the world.

Source: http://en.wikipedia.org/wiki/Fairy_Queen_(locomotive)