[1] Originally constructed as the Cheltenham and Great Western Union Railway, the line opened between Swindon and Kemble (with a branch to Cirencester) in 1841; it took an additional four years to complete the remaining sections.

At Standish Junction, just north of Stonehouse, it merges with the main line running between Bristol Temple Meads and Birmingham New Street.

It is said that the name was coined by Queen Alexandra, wife of King Edward VII, while travelling on a train along this route in June 1909.

Despite protests by local MPs,[6] the ORR made a preliminary decision that the project would not be included in the 2009–2014 High Level Output Specification plan for new rail infrastructure.

[7] In the 2011 Budget, the Government announced that funding for the redoubling would be provided, with works initially scheduled for completion by Spring 2014[8] but later delayed until August 2014.