Notes: The unstaffed halt's single platform was built up with ash and clinker, with the edge and facing using otherwise redundant sleepers. It was a mere fifty feet long and drivers had instructions to stop so that the guard's compartment was alongside. The amenities provided were a platform shelter and an oil lamp, with access by a footpath leading from what is now the A470. This footpath still exists but heavily overgrown and is about 120 yards south of the access road, also now heavily overgrown, installed for the transference of nuclear flasks by road to and from the power station. The halt was on a low embankment so it seems likely they were steps or a sloping path up to the platform although maps do not make this clear.

Trawsfynydd Lake Halt was, like most halts, passenger only and situated near the northeastern tip of Llyn Trawsfynydd. Many Nineteenth and early Twentieth Century institutions in Wales were given Anglicised names, this halt being one. Over the years, and especially since the Second World War, most have been rendered into Welsh or given both Welsh and English names. Trawsfynydd Lake Halt closed before this happened but had it been the name likely would have been Llyn Trawsfynydd Halt; 'Llyn' being Welsh for 'Lake'.

The line through the site of the future Trawsfynydd Lake Halt was opened in 1882 by the Bala & Ffestiniog Railway The company and line were subsequently taken over by the Great Western Railway (GWR) which went on to open the halt in 14 April 1934. Trawsfynydd Lake Halt was one of the 198 opened by the GWR between 1927 and 1939, in this case in pursuit of leisure business, in particular angling and walking, though the few locals on this upland rural area also made use of it.

Llyn Trawsfynydd is man made. It opened in 1928 as part of a hydro-electric power scheme. 'Reservoir Siding' was opened by the GWR in 1925 to serve firms building the dam and hydro-electric power station; It diverged towards the lake just north of the site of the future halt. This remained open but little used after the scheme opened. When the halt was opened the siding ended behind its waiting shelter but the siding's semi-slumber was not to last for in due course it was become the un/loading point for nuclear flasks for Trawsfynydd power station which commenced operation in 1965. It was to close in 1991 although in 2021 a plan was put forward for a new plant at the site using Small Modular Reactors and probably those manufactured by Rolls-Royce. Meanwhile decommissioning of the 1965 power station continues and will remain ongoing, at the time of writing, for many years to come. Lengthy decommissioning time, or more to the point the cost of it, is one of the drawbacks of nuclear plants. As a point of interest, Trawsfynydd was Britain's only inland nuclear power station and thus the only one not to draw water from the sea. Also Llyn Trawsfynydd was Britain's only inland body of water to supply two power stations operating on very different principles.

Llyn Trawsfynydd obtains it water from various sources including from Snowdonia and principally from the Afon Prysor which flows into the lake at its south-eastern tip and re-emerges at Maentwrog Dam, at the lake's north-western tip. Prior to the lake's creation the area it now occupies was marshy land, the flood plain of the Afon Prysor and no villages were lost. To cater for the nuclear power station the lake was expanded at its southern end. The hydro-electric plant is Maentwrog power station, a compact affair located some 1½ miles north-west of Maentwrog Dam, which is one of four dams controlling the water level of the lake, but does not directly provided water for the hydro-electric power station. Instead water is supplied via pipeline laid partly underground but mainly on the surface. The drop from lake to power station is in the region of 600 feet, thus gravity provides the impetus for water to drive the turbines. The exit from the power station is via a channel into the Afon Dwyryd and thence into the sea at Bae Ceredigion (Cardigan Bay). At the time of writing Maentwrog Hydro-Electric Power Station remained in operation and this relatively simple, clean form of generation is likely to do so for many years to come. Llyn Trawsfynydd is a relatively shallow lake, having an average depth of just four metres. 'Average' of course means the lake is deeper in some parts and shallower in others.

In later years at least, most trains were formed of just two carriages, with one regular turn comprising just one brake third coach. There were also some mixed trains which by British Railways days were becoming uncommon. These were trains formed of both passenger and goods stock, the latter being coupled at the rear and while it was a good economy measure on lightly used lines the downside, for passengers, was the time spent shunting at stations. Workmen's trains had been a feature of the line from the outset and were the originally narrow gauge Ffestiniog & Blaenau Railway's biggest source of revenue. Such a service between Trawsfynydd and Blaenau Ffestiniog survived until the line's closure to passengers. Workmen's trains in time became famous for the use an ancient rolling stock no longer suitable for general service and what became the National Coal Board was especially famous in this respect. In the context of this feature, workmen's trains used a dedicated siding at Blaenau Ffestiniog at which the men had to board and alight from and to ground level.

An extract from the 1931 GWR Route Availability diagram, showing the Blaenau Ffestiniog - Bala line as being Yellow. The diagram of course predated Trawsfynydd Lake Halt which was situated between Maentwrog Road and Trawsfynydd. For further explanation see the text below.

Railway companies had by necessity systems of Route Availability which indicated maximum axle weights permissible on their lines. Commonly abbreviated to 'RA' restrictions are indicated in numerical form which is stated on locomotives. For example the BR Class 24 diesel locomotives, which were a common sight in North and Central Wales, varied between RA5 and RA7. The higher the number the higher the axle weight of a locomotive although the waters are muddied somewhat by the number of axles a locomotive has; in general the more axles there are the lighter the axle load. The 'RA' system remains in use today. The Great Western Railway, always wanting to be different, used a system of colour codes and these were displayed on locomotive cab sides in the form of coloured, solid circles. If no such circles were displayed it meant so-unmarked locomotives could operate over any route and the 1400 Class 0-4-2Ts were one such, for example. At one time the line between Bala and Trawsfynydd was coded Blue and from there to Blaenau Ffestiniog coded Yellow but at the time the above diagram was issued the entire line was coded Yellow. While unconfirmed the Blue section may have been the reason why, in accordance with locomotive diagrams, some trains ran only between Bala and Trawsfynydd. It is known that on occasion 2251 Class 0-6-0 tender locomotives appeared on the line and these were coded Yellow, otherwise and in later steam years at least the predominant motive power on the line was various classes of 0-6-0PT (Pannier Tank) and the aforementioned 1400 Class 0-4-2T's although the latter seemingly became increasingly uncommon towards the end as a through line.

As happened across Britain and elsewhere, road transport began to eat into the railway's business during the inter-war period and from 1948 the Nationalised British Railways, then part of the British Transport Commission, began to look at making economies and this is why many miles of railway closed, at least to passengers, in the year prior to publication of 'The Reshaping of British Railways' in 1963 and which itself had its roots in the so-called Stedeford Committee of 1960. The Bala - Blaenau Ffestiniog line was deemed unremunerative, which it likely had been for many years. A traffic survey was undertaken in the late 1950s and with regard to Trawsfynydd Lake Halt the average daily passengers was just one, although this was not untypical for remote halts and indeed some rural stations at the time.

Military traffic had ended and, apart from a finite contract to bring cement to Blaenau in connection with the construction of Ffestiniog Power Station freight traffic was not heavy, most arriving and leaving Bala did so from and to the south and that to Blaenau Ffestiniog could be handled from the Conwy Valley Line northwards. It was all very telling. In 1957 Parliament authorised Liverpool Corporation to flood a section of the line by damming the Afon Tryweryn, not far from Bala. Funds were made available, perhaps surprisingly, to divert the route round the resulting lake and dam, but it was decided that improving the road from Bala to Llan Ffestiniog would be of greater benefit. Today the abandoned trackbed can be seen, especially when the water level is low, disappearing into the water, Llyn Celyn, just north of the site of Capel Celyn Halt. The trackbed then reappears just east of the site of Tyddyn Bridge Halt on the east side of the dam.

Road transport alternatives were established for groups such as schoolchildren and workers. The plans afoot for rail serving Trawsfynydd nuclear power station were to be catered for by building the long-discussed cross-town link between the two Blaenau Ffestiniog standard gauge stations. The estimated financial savings to be made were £23,300 by withdrawing the passenger service and £7000 in renewal charges. While these sums may sound minuscule it must be remembered this was well over half a century ago. In April 2025 for example the aforementioned £23,300 in 1960 equates to £465,454 [Source: Bank of England]. If we assume similar figures applied to many other now-defunct rural railways it becomes easy to understand the dilemma facing British Railways and Governments of the 1950s and 1960s.

The halt closed from 4 January 1960, as did the entire line north of Bala (Bala closed on 18 January 1965 along with the Ruabon - Barmouth line) to passengers but goods trains continued to pass the site for a further year. In 1964 the by-then-disused line reopened from Blaenau Ffestiniog southwards to Reservoir Siding, where a large 'Goliath' gantry crane was erected to load and unload traffic for the then new Trawsfynydd nuclear power station. The main goods transported were nuclear fuel rods carried in nuclear flasks. The line from the junction with Reservoir Siding to the halt was left in place for shunting purposes, though the halt itself was not used in any way.

Passenger trains briefly returned to the line in 1989 to a temporary platform at Maentwrog Road. These trains ran for one summer in an attempt to encourage tourism at the power station. Few people used the service to visit the power station, most travelled 'just for the ride', so the following year tourist trains ran to the line's terminus near the remnants of Trawsfynydd Lake Halt then reversed, with no-one getting on or off. This service lasted until the end of the 1990. Rail enthusiasts' special trains traversed the line from time to time. Notable examples were two 'last trains'. The first ran from Bala to Blaenau Ffestiniog and return on 22 January 1961 and was the Stephenson Locomotive Society (Midland Area) Last Passenger Train Bala to Blaenau Ffestiniog and in the post-1964 era the Hertfordshire Rail Tours Trawsfynydd Lament ran southwards to the limit of line at the power station loading point on 17 October 1998, the line having become redundant following removal of spent nuclear fuel from the power station. There was also R.C.T.S. / L.C.G.B. (North West Branches) Ffestiniog Rail Tour on 11 October 1969. British Rail / Gwynedd County Council Trawsfynydd Branch Line Tour on 6 August 1989.

Following the 1964 reinstatement, for which much money was spent, nuclear flask trains were typically worked by BR/Sulzer Type 2 locomotives which became Class 24. After the rundown and withdrawal of this class, the upgraded variant which became Class 25 became a common sight. After this, tradition went out of the proverbial window and various of Brush Type 2 (Class 31), English Electric Type 3 (Class 37) and Brush Type 4 (Class 47) could be seen. It is recorded that the last official flask was on the 8 August 1995 hauled by 31255 adorned with a headboard followed by another 31.  The last actual flask was on 22 April 1997 hauled by 37426 but not before much effort had been made to reballast the line only the previous year. The very last train was a railtour, worked by Nos. 56108 and 47785, ran on 17 October 1998 following which the line once again fell into disuse. The 'Goliath' gantry crane was dismantled and removed by road in 2005. The speed limit along the line between Blaenau Ffestiniog and the power station siding was just 15mph.

As already mentioned, numerous railtours along with engineering and weedkilling trains traversed to line prior to 1998 and these produced a variety of motive power from diesel multiple-units to Class 20 and Class 59 locomotives. There was one particularly interesting event in April 1992. In 1986 British Rail had introduced its 'Super Sprinter' diesel multiple-units intended for use in West Yorkshire. Forty-two two-car units were built but due to an urgent need to replace 'First Generation' units, ostensibly Classes 121 and 122, 35 of Class 155 were disbanded and rebuilt into single-unit railcars forming the 70-strong Class 153. The intention was the use these on the Conwy Valley Line (Llandudno Junction - Blaenau Ffestiniog) and to that end No. 153307 was sent to the line for clearance tests, This included two round trips to the end of the line at the nuclear flask siding but why this was deemed necessary remained a mystery at the time of writing.

By 2015 the only evidence that the halt ever existed was the decaying platform buried deep under foliage, although in Spring 2016 the 'mothballed' line still ran to the site and to the former nuclear flask loading point.

Between 2000 and 2011 there were at least two attempts to put the remaining line to use. In 2011 there were proposals to use the rails as a recreational velorail track. Neither this nor the earlier idea came to anything. The possibility remains that the surviving line could see future preservation or reuse by the nuclear industry.

To considerable local surprise fresh moves to reopen the line from Blaenau as far south as Trawsfynydd began in September 2016, with the formation of The Trawsfynydd & Blaenau Ffestiniog Community Railway Company. At least one regional newspaper reported that "Volunteers are set to start work this weekend on clearing vegetation from the trackbed between Blaenau Ffestiniog and Trawsfynydd." The company was quoted as saying "We have been given a licence by Network Rail to clear and survey the line." By mid-October 2016 the company had achieved six working days of track clearance but unfortunately the group exceeded their authority and damaged a Network Rail bridge in an area they shouldn't have been working. The group have now disbanded and a new group, The Bala & Ffestiniog Railway Railway Heritage Trust was formed in 2018 to continue the campaign to reopen the line. However the trust with Network Rail was severely damaged and they became extremely wary of any further efforts in the area.

Tickets from Michael Stewart. Timetables from Timetable World

Sources and bibliography:

• Wikipedia
• Railway Passenger Stations in Great Britain, Michael Quick, Fifth Edition September 2023
• Cilnker's Register of closed Passenger Stations and Goods Depots in England, Scotland and Wales 1830 - 1877. C. R. Clinker, Avon Anglia Publications 1978. ISBN 0 905466 19 5
• Six Bells Junction (railtour web site)
• Timetable World
• Bala & Ffestiniog Railway Heritage Trust
• Dave Plimmer's Main Line Railways of North Wales web site shows locomotive diagrames from 1966 - 1984
• Larry Goddard's The Conway Valley Line 2004 Foxline Publishing. ISBN ‎ 1870119770