 In 1845 a blast furnace was started at Kinneil, processing the ironstone that was already being mined in the vicinity.The Slamannan proprietors arranged for friendly interests to promote a nominally independent company to get to Bo'ness, and the "Slamannan and Borrowstounness Railway" (S&BR) was authorised by Act of Parliament on 26 June 1846 to make the line.The main line from Causewayend to Bo'ness Harbour was to be 5½ miles long, with a spur from the E&GR line so arranged as to allow through running from the Polmont direction to Bo'ness.