The line opened in 1859 as a horse tramway, running from quays on the River Dyfi at Morben and Derwenlas, through the town of Machynlleth and then following the Dulas Valley north to Corris and on to Aberllefenni.

[1] By November 1850, the name had changed to the Corris, Machynlleth & River Dovey Railway or Tramroad which was planned to run down the Dulas Valley and then along the north shore of the Dyfi past Pennal to Pant Eidal, near the later main-line Gogarth Halt.

Following the plans for a 4 ft 8+1⁄2 in (1,435 mm) standard gauge railway along the Dyfi valley, these early proposals were shelved.

[4] In December 1857, a fourth bill was set before Parliament to create the Corris Machynlleth & River Dovey Tramroad (CM&RDT).

This was similar to the 1851 scheme, except that it proposed to cross the Dyfi near Machynlleth and then follow the south bank of the river, and proposed a tramway from the "machine house" (i.e. the slate mill) at Aberllefenni, down to the wharf at "Cae Goch on the River Dovey" (Cae Goch was near to the later main line Glandyfi station).

The opening of the standard gauge line to Borth made the section of the CM&RDT from Machynlleth to Morben obsolete.

It was much easier to transship slates to the main line at Machynlleth and most of the lower section of the tramway was abandoned, probably in 1869.

[6] In 1862, a new bill was deposited, seeking to extend the Upper Corris Tramway to iron ore mines at Tir Stent, near the pub at Cross Foxes.

[7] In 1863, a new transshipment wharf was built at Machynlleth to allow slate to be loaded from CM&RDT waggons into standard gauge wagons.

The original tramroad was laid with light bridge rail suitable for waggons to traverse as they were pulled by horses.

[9] In 1874, a new goods warehouse and horse stable was built besides the transshipment wharves at Machynlleth, this was later converted to form the first passenger station here.

[8] They also appointed Joseph R. Dix, son of the main-line stationmaster at Machynlleth, as Manager in succession to David Owen.

The second of these acts was necessary because the owners of the quarries served by the railway objected that passenger trains would interfere with their mineral traffic.

Initially the railway ran a test passenger service on the local roads; this proved to be so popular that they were able to pass the act of Parliament over the opposition of the quarry owners.

It was also the first instance of a long history of the Corris Railway operating passenger road services in the area.

[10] A semi-official passenger service had been running since the early 1870s using adapted waggons to convey quarry workers and visitors.

This was promoted as part of a circular "Grand Tour" which took in the two narrow gauge railways and the Cambrian service between Tywyn and Machynlleth.

[13] Following a dispute with the directors, Dix was dismissed in June 1907,[14] and replaced by John J O'Sullivan (formerly of the Cork, Blackrock and Passage Railway).

O'Sullivan had died in office in 1917; the parent company's Secretary, Frederick H Withers, acted as manager until a new manager, Daniel J McCourt (who had worked on Imperial's Middlesbrough system until that was taken over by the local municipality) took over in 1921 and was responsible for developing and extending the connecting bus services as partial compensation for the decline in rail traffic.

While the GWR did not relish owning another Welsh narrow gauge line, they did perform some track maintenance, and on at least two occasions the rolling stock was repainted.

While the GWR had tolerated the Corris, BR was looking for an excuse to close the loss making railway.

The waters began to undermine the Corris Railway embankment on the south side of the Dovey Bridge, and although the track was never breached, it was the excuse that BR needed to close the line.

The Aberllefenni to Corris section was lifted in November 1948, and 10 tons of the rail was purchased by Henry Haydn Jones for use on his Talyllyn Railway.

[17] In the early 1960s a group of volunteers from the Talyllyn Railway, led by Alan Meaden, began visiting Corris.

Initially the Society sought to purchase Machynlleth station for its museum,[19] but when this proved impossible it turned its sights elsewhere.

The railway is also actively pursuing a southwards extension towards Machynlleth, with the initial aim of extending the line to Tan-y-Coed, midway between Esgairgeiliog and Llwyngwern and some 21⁄2 miles south of Corris.

As always, this is involving lengthy negotiations with the authorities, not least due to the line south of Maespoeth running immediately adjacent to the A487 trunk road.

Carriage 20 is similar in appearance to the bogie vehicles, but on a shorter, ex-National Coal Board four-wheel chassis.

Carriage 21 has been designed to appear as similar as possible to the original 19th Century bogie vehicles, but constructed to 21st Century safety standards with a steel chassis based on the Talyllyn Railway's standard bogie carriage design and a steel skeleton with timber cladding for the body.

From the completion of fitting-out in September 2015 the railway was again able to run an authentic-looking "1920s" train with the "Tattoo" locomotive and two bogie carriages.