The GWR planned a line to reach Weymouth, and it promoted a nominally independent company, the Wilts, Somerset and Weymouth Railway, which started construction from near Chippenham. It was taken over by the GWR on 14 March 1850, but progress in building towards Weymouth was slow; it finally reached the town via Yeovil and Dorchester, on 20 January 1857. The line had a separate station at Dorchester, and a connecting link was made to the Southampton and Dorchester (now LSWR) line. The GWR was required by the terms of its authorising Act of Parliament to give running powers to the LSWR over the line from Dorchester to Weymouth, and "mixed gauge" track, that is track with rails both for broad gauge trains and narrow gauge trains, was provided.