The 12123 / 12124 Deccan Queen is a daily Indian passenger train service operated by the Central Railway zone of the Indian Railways connecting the cities of Mumbai and Pune. Introduced on June 1, 1930, the Deccan Queen was India's "first superfast train, first long-distance electric-hauled train, first vestibuled train, the first train to have a ‘women-only’ car, and the first train to feature a dining car". The service name comes from the Marathi nickname "दख्खन ची राणी", a popular nickname for Pune. Deccan Queen is currently the fastest train service linking Chhatrapati Shivaji Maharaj Terminus and Pune Junction. It has an average operating speed of 60 km/h (37 mph) including stops, and a top speed of 105 km/h (65 mph). The train's long history and common use as a commuter train has gained it significant popularity, including annual celebrations of its "birthday" on June 1 at Pune Junction. It was hauled by a Kalyan-based WCAM-3 end to end up until June 2022. From June 2022, its upgraded coaches in a new livery are being hauled by a Ajni-based WAP-7.

Central Railway is one of the 19 zones of Indian Railways. Its headquarters is in Mumbai at Chhatrapati Shivaji Maharaj Terminus. It has the distinction of operating the first passenger railway line in India, which opened from Mumbai to Thane on 16 April 1853.