The Sialkot-Narowal Railway was a broad gauge(BG) line with a length of 38 miles(63km) that opened in Nov 1915 from Sialkot and completed to reach Narowal in Jan 1916. The line was constructed by the North Western Railway (NWR) for the ‘Sialkot-Narowal Railway Company’ and worked by NWR as part of its network  .
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/8/19/1429 “Sialkot-Narowal Railway Company Limited, Indenture between the parties; 1917"
- L/AG/46/34/1 “Copies of agreements with the Secretary of State, including those relating to the following lines worked by the (North Western Railway) Company, 1893-1924: Larkana-Jacobabad (Sind) Light Railway; Sialkot-Narowal Railway; Upper Sind Light Railway; Hoshiarpur Doab Branch Railways; 1893-1924"
- L/F/8/20/1778 “Sialkot-Narowal Railway Company Limited, Suplementary contract relating to the incidence of cost of effecting Narowal Junction; 1933"
- " Administration Report on the Railways in India – corrected up to 31st March 1918"; Superintendent of Government Printing, Calcutta; page 119; Retrieved 22 Jun 2018
- Wikipedia "Sialkot"; Retrieved 22 Jun 2018
- “Industrial Railways and Locomotives of India and South Asia” compiled by Simon Darvill. Published by ‘The Industrial Railway Society’ 2013. ISBN 978 1 901556 82-7. Available at https://irsshop.co.uk/India. Reference: Entry RC38 page ....
- “British Library Archives and Manuscripts Catalogue” - Search; Retrieved 27 Jan 2016