Central Wales Railway Extension letter of 1865
The Central Wales Extension Railway was incorporated by an Act of Parliament of 3 July 1860 to take the line as far as Llandovery. This was a further distance of 26¼ miles, and was completed in four sections: (i) Llandrindod to Builth Road, 5 miles, opened 1 November 1866; (ii) Builth Road to Garth, opened 11 March 1867; (iii) Garth to Llanwrtyd, opened 6 May 1867; and (iv) Llanwrtyd to Llandovery, including the Sugar Loaf tunnel, completed 1 June 1868. The Central Wales Extension Railway was formally opened 8 October 1868.
By 1868 the London and North Western Railway had absorbed all three of these companies (which had in any case been primarily concerned to get the lines built and had no real interest in the day-to-day running of rolling stock). The LNWR shared the Vale of Towey Railway with the Llanelly Railway. In 1867 the Llanelly Railway had opened a line to connect Pontardulais with Swansea: in 1871 the LNWR won a legal battle to to give it control of this line. The rest of the Llanelly Railway's interests were absorbed by the Great Western Railway