The Baran-Kotah Railway was a broad gauge(BG) extension constructed by the State and worked by the Great Indian Peninsula Railway(GIPR). The first section from Baran opened in 1907; reaching Kotah in 1909 connecting to the Nagda-Mathura(Muttra) Railway section of the Bombay, Baroda and Central India Railway(BB&CIR). The total length of the line was 40 miles(64km) 
See Great Indian Peninsula Railway(GIPR)
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/8/17/1216 “Great Indian Peninsula Railway Company, Contract for working the Baran-Kotah Railway; 1909”
Also the following IOR records relating to Staff employment are listed and may provide information concerning this railway:-
- L/F/8/1-20 "Appointments to State Railways made in the UK; 1855-1946"
- Z/L/F/8/1-2: "Index to Appointments to State Railways made in the UK; 1855-1946"