Refer to attached snippet from the 'Report by the Railway Board on Indian Railways for 1937-38".
Inaugurated as a weekend special on 17th April, 1937. Initially, the Down train left Bombay on every Saturday afternoon, reaching Surat in the night. The Up train departed from Surat early on Mondays, reaching Bombay late morning.
Due to the overwhelming popularity of the train, it was converted into a daily service from 24th May, 1937.