Due to the proximity of
Dhanbad, the coal capital of India, to key coal and industrial regions in West Bengal (
Asansol,
Raniganj,
Andal,
Waria,
Durgapur) and its closeness to
Kolkata, a large number of passengers travel this route daily. However, with population growth and industrial expansion, the sole superfast connection, the
Howrah–Dhanbad Coalfield Express, couldn't meet rising demand. As a result, a new train was truly needed. In response, the Howrah–Asansol Fast Passenger, inaugurated around 1954, was extended to Dhanbad in 1964, and renamed the Dhanbad Express. It later became the Black Diamond Express around 1970. The Black Diamond Express serves as a counterpart to the Coalfield Express but is operated by
East Central Railway, while the Coalfield Express is managed by
Eastern Railway. The Black Diamond Express runs on the
Howrah – Barddhaman Main line, unlike the Coalfield Express, which uses the
Howrah – Barddhaman Chord line. Additionally, the Black Diamond Express operates in the morning, complementing the evening Coalfield Express. == Service ==