When the Great Western Railway (GWR) opened its first main line from London to Bristol, the ancient Borough of Malmesbury was not on the route, and Chippenham station, ten miles away became the railhead for coach services from the town.

[note 1][1][2] The W&GR was to run from Stroud via Nailsworth and Malmesbury to Christian Malford; ostensibly connecting two GWR routes.

It is not clear why it could not continue as an ally of the GWR alone, but it suspended all expenditure, and attempts to revive the scheme proved futile.

In addition, tension between the main contractor Budd & Holt and the company's engineer Ward led to delays and an arbitration award, and the construction was heading for an overspend.

Early in 1877 it emerged that a further £19,000 was required to complete the line and to settle claims from Budd & Holt; the company planned to go to Parliament for supplementary powers to raise the money, but were persuaded to obtain the funding by local loans instead.

The remaining works were swiftly executed, and Colonel Yolland of the Board of Trade inspected the line on 20 November.

On 14 December Colonel Rich of the Board of Trade carried out a final inspection for passenger operation, finding it satisfactory subject to minor signalling changes at Dauntsey, the main line junction.

The junction with the GWR main line was at Dauntsey, between Swindon and Chippenham, where branch trains had a bay platform.

The line was 6 miles 4 furlongs and 11⁄2 chains (10.5 km) in length; there was a tunnel at Malmesbury, and the station there was on Gloucester Road just beyond Stanes river bridge.

On 3 March 1880 torrential rainstorms resulted in floodwater in the River Avon, which damaged Poole's Bridge, between Dauntsey and Somerford.

[2] At this time the Great Western Railway route from London to South Wales ran from Swindon to the Severn Tunnel via Box.

The company was spurred by a rival scheme to consider shortening the route, and the South Wales & Bristol Direct Railway, an offshoot of the GWR, was authorised in 1896.

This was approved, and the main construction work, a connecting link at Little Somerford on a gradient of 1 in 50 up to the Badminton line, started on 9 May 1932.

From July 1934 the configuration was changed to give access from the Somerford end, a connection being laid in specially, referred to as Kingsmead Siding.

Goods traffic continued on the branch; Malmesbury signal box was abolished in 1956, with the yard points being hand worked.