The engineer in charge of the construction was Peter W. Barlow and the contractors were Messrs. Hoof & Son. In April 1845 the SER decided that the branch would be double track. A tunnel was required after leaving Tunbridge. This was named "Somerhill Tunnel" after the nearby mansion. A mile and 54 chains (2.70 km) after leaving Somerhill Tunnel, a viaduct was required. Southborough Viaduct stands high and has 26 arches. A temporary station was built at Tunbridge Wells as the Wells Tunnel was still under construction. It was from Tunbridge. The temporary station subsequently became a goods station. The first train, comprising four locomotives and 26 carriages, arrived at Tunbridge Wells on 19September. Trains from Tunbridge had to reverse before starting the climb to Somerhill Tunnel, as there was no facing junction at Tunbridge. This situation was to remain until 1857, when a direct link was built at a cost of £5,700. The old link remained in use until 1913.