Katakhal Lalbazar Railway
The Katakhal-Lala Bazar Railway Co. Ltd. was a Company incorporated on 23 December 1915. The metre gauge(MG) line of 28 miles (45km) was sanctioned for construction by the Assam-Bengal Railway(ABR) in 1916  The line was under construction in 1921-22 
The date of opening of the railway is unknown. In 1923 the Assam-Bengal Railway(ABR) were contracted by the Government of India(GoI) for the ‘working, maintenance and management' of the Katakhal-Lalabazar Railway.
In 1952 the Katakhal-Lala Bazar Railway was being ‘worked by the Assam Railway'.
The Assam Railway was formed on partition in 1947 on the breakup of the Bengal and Assam Railway(B&AR); which had been created in 1942 from the ABR
So it seems probable that the Katakhal-Lala Bazar Railway had been worked by ABR from opening until 1942; then by its successor B&AR until partition.
Refer to FIBIS Fact File #4: “Research sources for Indian Railways, 1845-1947” - available from the Fibis shop. This Fact File contains invaluable advice on 'Researching ancestors in the UK records of Indian Railways' with particular reference to the India Office Records (IOR) held at the British Library
An on-line search of the IOR records relating to this railway  gives the following: -
- L/ F/8/20/1696 “Assam-Bengal Railway Company Limited, Contract for the working, maintenance and management of the Katakhal-Lalabazar Railway; 1923”
- "Administration Report on the Railways in India – corrected up to 31st March 1918"; Superintendent of Government Printing, Calcutta; page 156; Retrieved 25 Jan 2016
- “Report on the Administration of North East India 1921-1922”, Chapter iv, page 122 Reprinted by Google Books, 2003. Mittal Publications,Delhi
- “British Library Archives and Manuscripts Catalogue” - Search; Retrieved 25 Jan 2016