The line continues through North Bengal and western part of Assam to connect with Guwahati.

The first lap was a 185 km journey along the Eastern Bengal State Railway from Calcutta Station (later renamed Sealdah) to Damookdeah Ghat on the southern bank of the Padma River, then across the river in a ferry and the second lap of the journey.

A 336 km metre-gauge line of the North Bengal Railway linked Saraghat on the northern bank of the Padma to Siliguri.

Presently, it is between the Paksey and Bheramara stations on the broad-gauge line between Darshana and Parbatipur in Bangladesh.

With the partition of India in 1947, a major portion of the Calcutta–Siliguri line ran through East Pakistan, now Bangladesh.

A generally acceptable route to Siliguri was via Sahibganj loop to Sakrigali ghat.

Indian Railways constructed a new broad-gauge rail link from south Bengal.

New Jalpaiguri, a new broad-gauge station was built south of Siliguri Town.

[5] The 2,240 m (7,350 ft) long Farakka Barrage carries a rail-cum-road bridge across the Ganga.

The rail bridge was opened in 1971 thereby linking the Barharwa–Azimganj–Katwa loop to Malda Town, New Jalpaiguri and other railway stations in North Bengal.

The Kishanganj branch of the Darjeeling Himalayan Railway was taken over and converted to metre gauge.

Bangladesh started export of fertilizer to Nepal utilizing the Rahanpur–Singhabad transit point in November 2011.