The topography of the district was challenging, and a practicable line had to be routed north of the most mountainous region, and climb steeply.

Newtown and Llanidloes were centres of flannel manufacture at the time, and in frustration promoted their own railway joining the towns.

This was authorised in 1855 and opened in stages from 1860, connecting to the Shrewsbury and Chester Railway, and thence the developing English network, at Oswestry in Shropshire.

[1][2][3] There was still a considerable expanse of undeveloped territory to the west and south of Newtown, and thoughts returned to railways covering longer distances.

A line striking across Wales from northeast to the southwest, possibly developing an Atlantic coast port, seemed attractive, and this led to several ambitious schemes which was later attempted to be built by the Manchester and Milford Railway.

Avoiding the mountainous area surrounding Plynlimon, the easiest and obvious route lay in a sweep north through Talerddig to Machynlleth, an important market town.

A solicitor based there, named David Howell, made energetic moves to form a railway scheme, beginning with a public meeting on 20 December 1856 at Machynlleth.

[2][3][5][6][7] A contract for the construction was let to the partnership of David Davies and Thomas Savin, in the amount of £130,000, of which £23,000 was to be paid in paid-up shares and £5,000 as a loan.

Briwnant-Jones suggests that the rock material was found to be suitable for the construction of bridges on the line, and that the change had a beneficial effect on the contractors' costs.

Savin had plans to develop the coastal area from Aberystwyth northwards as far as Pwllheli, including the construction of hotels and other amenities.

Davies was more cautious, seeing this as reckless overreaching, and the difference of view led to the partnership breaking up on 29 October 1860.

[10][3][2] The GWR negotiated further but sought to impose conditions which the N&MR found unacceptable, and in December 1862 the discussions were at an end.

[14] It was to build a line from Aberystwyth to Pwllheli, crossing the River Dyfi, anglicised as Dovey, near its mouth by a large bridge.

The former Newtown and Machynlleth line continues in use, and carries the passenger service between Shrewsbury to Aberystwyth and Pwllheli.

From Moat Lane Junction the line climbed westbound steeply to Talerddig, 10 miles (16 km), in part at 1 in 80.