[7][8] Since preservation, the railway has operated as a tourist attraction, expanding its rolling stock through acquisition and an engineering programme to build new locomotives and carriages.

The finished slates were sent by packhorse to the wharf at Pennal, transferred to boats for a river trip to Aberdyfi (also spelled as Aberdovey), and then finally loaded into seagoing vessels, a complex and expensive transportation arrangement which limited the quarry's output.

In January 1864, McConnel formed the Aberdovey Slate Company, which leased the land including Bryn Eglwys from the landowner, Lewis Morris of Machynlleth.

He focused on providing rail transport for the isolated quarry, and in April 1864 he reached agreement with local landowners to purchase the land necessary to build a railway towards Tywyn and onwards to the port of Aberdyfi.

By September 1866 construction had advanced to the point where the Board of Trade inspector Captain Henry Tyler could make an initial inspection and report.

[3] During November of that 1866, Tyler returned to Tywyn and re-inspected the railway following which, subject to some further minor improvements, he approved its formal opening for passenger service.

[24] The railway opened with two locomotives, one carriage and several goods vehicles in use and was operated under a "one engine in steam" policy to ensure that two trains could not collide.

Coal, building materials and general goods were delivered down the incline and the contents of the village cesspits were hauled back up for disposal along the lineside.

[33] The last two decades of the 19th century saw a decline in the demand for slate and many smaller quarries fell on hard times, including Bryn Eglwys, where by 1890 production had halved to 4,000 long tons (4,100 t) a year.

McConnel expanded production at Bryn Eglwys to take advantage of the sudden demand, but only with the aim of maximising profits during the remainder of his lease, which was to expire in 1910.

[40] On 2 July 1950 Haydn Jones died and closure of the railway seemed inevitable, but the line continued to operate for the remainder of the summer season, ending on 6 October.

With the support of the meeting, the committee – with Rolt as chairman and Whitehouse as Secretary – met for the first time on 23 October and immediately entered into negotiation with Haydn Jones' executors.

[44] The railway re-opened under the control of the Society for the first time on the Whit Monday bank holiday, 14 May 1951,[45] with trains running between Wharf and Rhydyronen stations.

This problem was eventually cured by relaying the railway to its correct gauge and altering Talyllyn's trailing wheels to allow them to swivel horizontally, shortening the locomotive's fixed wheelbase.

This locomotive was built for the depot railway serving RAF Calshot where it worked until 1945, and, after rebuilding from its original 2 ft (610 mm) gauge, it entered service in 1954.

[52] Through the 1950s the volunteers and staff members of the TRPS rebuilt the line and rescued it from its state of decay, during a period characterised by a "Boy's Own comic spirit of adventure, involving enthusiasm, ingenuity and a fair degree of irresponsibility".

[53] On 22 May 1957 the BBC produced a live outside broadcast from the railway, during which Wynford Vaughan Thomas and Huw Weldon commentated on a trip from Dolgoch to Abergynolwyn.

In 1954 the Preservation Society agreed to start work on a formal museum, and exhibits from around the United Kingdom were acquired to form the nucleus of the collection.

A loop was installed at Wharf in 1952, being used from the start of the 1952 season, to avoid having to propel trains to Pendre,[60] but in the winter of 1964/65 a major upgrade of the station was carried out.

[77] In April 2012 locomotive No.2 Dolgoch appeared at the Steel Steam and Stars Gala at the Llangollen Railway, running on a temporary section of narrow gauge track.

[80] In 2021, the Slate Landscape of North-west Wales, which includes the Talyllyn Railway and Bryn Eglwys Quarry, was designated a World Heritage Site.

[85] Since 1984 there has been an annual running event called Race the Train, which follows the railway track 7 miles (11 km) from Tywyn to Abergynolwyn and back again.

Leaving Wharf station, which stands at an elevation of 40 ft (12 m) above sea level, the line passes immediately under the A493 Machynlleth to Dolgellau road and enters a long cutting that climbs towards Pendre, at a maximum gradient of 1 in 60.

[60] From Pendre, the railway passes over a gated level crossing and runs beside an industrial estate before climbing up to Ty Mawr bridge and on to Hendy, the first of five minor halts, which serves the adjacent farm.

Shortly after crossing over the forestry road the line reaches Tŷ Dŵr, where the original locomotive shed stood from 1865 until it was demolished after Pendre works opened in 1867.

From here the line runs into the gorge, high above the river on a narrow ledge, ending at the foot of the first incline leading to the Bryn Eglwys quarry.

[64] Until the closure of the quarries in 1946, the line east from Abergynolwyn was worked as a mineral tramway – only slate and goods trains serving Bryn Eglwys ran on this section.

Before preservation, the railway operated a "one engine in steam" policy, but with growing passenger numbers it became necessary to install passing loops and a more stringent method of single line control was introduced.

The railway has few signals; instead it has stop boards at Pendre, Brynglas, Quarry Siding and Nant Gwernol, and the blockman allows trains to proceed by use of flags.

[115] The preservation of the Talyllyn Railway by volunteers was the inspiration for the 1953 film The Titfield Thunderbolt,[116] an Ealing Studios comedy about a group of villagers attempting to run a service on a disused branch line after closure.