The Nalhati-Azimganj Railway was the original section of the line constructed in 1863 by the ‘Indian Branch Railway Company’. Also referred to as the 'Nulhati-Murshidibad Tramway' in some early records. The line used a 4ft(1222mm) unique rail gauge and ran from Nalhati only far as Azimganj, a distance of 27 miles (43 km) .
‘Nulhatee Railway’ is the name used in the ‘Administration Report for India 1871-72’ to describe this line. “This line has become one of what are denominated ‘State’ lines, Government having purchased it for 30,000/. from the Oude and Rohilkund Company. It was constructed by this company on a 4' 0" gauge as the Indian Branch Railway Company” 
- “Administration Report on Railways 1918” page 55 (pdf64); Retrieved 7 May 2017
- "Bengal District Gazetteer - Mukshidabad" by L S S O’Malley, Indian Civil Service, Calcutta . Pages 150-151; Retrieved 24 Dec 2015
- Google Books pdf page 561 and British Library ‘India Office Records’ L/PARL/2/100 “Railways in India for the year 1871-72” by Juland Danvers , Government Director of the Indian Railways - presented to both Houses of Parliament; Paras 82-83; pages 36-37; Retrieved 23 Jun 2018