Llanidloes development into a major junction station arose because of the rapid and chaotic growth of the Victorian railway network in Great Britain.

Further work west of Llangurig is visible on Google Earth and Victorian OS Maps including the portals of the summit tunnel at Blaen Myherin.

[2] In response, another Act of Parliament was passed in 1862, giving the jointly owned Llanidloes and Newtown Railway (L&NR) (which was managed by the Cambrian Railways since 1860) the rights to extend southwards from Llanidloes with 1.5 miles (2.4 km) of double track to Penpontbren Junction where the M&MR line would diverge to Carmarthen and the MWR line would continue to Builth Road (serving Builth Wells).

The commercial rivalry between the rail companies meant Llanidloes station would no longer be just a small country stop between Newtown and Builth Wells.

The line beyond Llangurig to Strata Florida for Carmarthen was abandoned after initial works to the summit tunnel including both north and south portals.

The M&MR was diverted west from Strata Florida to Aberystwyth; the remaining 1.5-mile spur from Penpontbren Junction to Llangurig was lifted in 1882 after carrying one demonstration freight train.

But before the Beeching Axe or the transfer occurred, the entire former Mid Wales Railway system was closed to passengers on 31 December 1962.