Restoration of the Ffestiniog Railway as a tourist railway had begun in 1952, but the construction of the power station would sever the link between Porthmadog and Blaenau Ffestiniog by flooding the northern portal of the Moelwyn Tunnel and the trackbed to its north, and constructing access roads along the trackbed to the south of Tanygrisiau station.
Railway restoration was in its infancy in Britain, and although the Ffestiniog Railway opposed the Bill during its final stages through Parliament, the scheme was written off as "old gentlemen and boys playing trains".
The Act of Parliament to authorise the power station was granted on 16 May 1955.
The Railway received a "Notice to Treat" on 5 February 1956, and a "Notice to Enter", which can normally be up to three years after the first notice, on the following day.
Moelwyn Tunnel was requisitioned on 2 June 1958, with two days between the notices.

The Ffestiniog Railway began legal proceedings to obtain reasonable compensation for the loss of their line in 1956, and it had become the longest case in British legal history by the time it was finally settled in 1972, sixteen and a half years later.
Relationships between the two parties were not good in the early days, as the Central Electricity Generating Board (CEGB) were convinced that the Ffestiniog Railway board had bought a moribund railway in order to pocket the compensation themselves.
Charles Goode produced plans for a new route along the western side of the lake, which it was agreed would be incorporated into the plans.
However, the CEGB then moved the location of the switching station, rendering the route impractical, and the consulting engineers Livesay & Henderson produced an east side route, which was much more expensive to implement.
The Ffestiniog Railway was aiming for "equivalent reinstatement", where the British Electricity Authority, subsequently the Central Electricity Generating Board, would pay the full cost of building a replacement route.
Based on the cost of the east side route, the Lands Tribunal ruled that equivalent reinstatement would only be justified if passenger number were to rise from 76,000 to 196,000, which was not deemed to be "within the bounds of the possible", despite the fact that these figures were reached in 1967.

Eventually, a scheme called "deferred maintenance" was devised, and formed the basis for the final payout.
Pressure was applied to the CEGB during the final hearings at the Lands Tribunal, to allow a west side route, and the Ffestiniog Railway were awarded £65,000, an interest payment of £30,000, and legal costs.
The full text of the decision is published in Brian Hollingworth's book, and fills fifteen pages.
Whereas most of the reinstated route, which included a spiral at Dduallt and a new Moelwyn Tunnel, was built by volunteers, the section immediately behind the power station was built by Sir Alfred McAlpine (Northern) Ltd, as it included four buried bridges to carry the trackbed over the inlet penstocks to the power station.
Restoration of the Ffestiniog Railway as a tourist railway had begun in 1952, but the construction of the power station would sever the link between Porthmadog and Blaenau Ffestiniog by flooding the northern portal of the Moelwyn Tunnel and the trackbed to its north, and constructing access roads along the trackbed to the south of Tanygrisiau station. Railway restoration was in its infancy in Britain, and although the Ffestiniog Railway opposed the Bill during its final stages through Parliament, the scheme was written off as "old gentlemen and boys playing trains". The Act of Parliament to authorise the power station was granted on 16 May 1955. The Railway received a "Notice to Treat" on 5 February 1956, and a "Notice to Enter", which can normally be up to three years after the first notice, on the following day. Moelwyn Tunnel was requisitioned on 2 June 1958, with two days between the notices.
The Ffestiniog Railway began legal proceedings to obtain reasonable compensation for the loss of their line in 1956, and it had become the longest case in British legal history by the time it was finally settled in 1972, sixteen and a half years later. Relationships between the two parties were not good in the early days, as the Central Electricity Generating Board (CEGB) were convinced that the Ffestiniog Railway board had bought a moribund railway in order to pocket the compensation themselves. Charles Goode produced plans for a new route along the western side of the lake, which it was agreed would be incorporated into the plans. However, the CEGB then moved the location of the switching station, rendering the route impractical, and the consulting engineers Livesay & Henderson produced an east side route, which was much more expensive to implement. The Ffestiniog Railway was aiming for "equivalent reinstatement", where the British Electricity Authority, subsequently the Central Electricity Generating Board, would pay the full cost of building a replacement route. Based on the cost of the east side route, the Lands Tribunal ruled that equivalent reinstatement would only be justified if passenger number were to rise from 76,000 to 196,000, which was not deemed to be "within the bounds of the possible", despite the fact that these figures were reached in 1967.
Eventually, a scheme called "deferred maintenance" was devised, and formed the basis for the final payout. Pressure was applied to the CEGB during the final hearings at the Lands Tribunal, to allow a west side route, and the Ffestiniog Railway were awarded £65,000, an interest payment of £30,000, and legal costs. The full text of the decision is published in Brian Hollingworth's book, and fills fifteen pages. Whereas most of the reinstated route, which included a spiral at Dduallt and a new Moelwyn Tunnel, was built by volunteers, the section immediately behind the power station was built by Sir Alfred McAlpine (Northern) Ltd, as it included four buried bridges to carry the trackbed over the inlet penstocks to the power station.
Ffestiniog Power Station