The isolated Holyhead Breakwater Railway was probably more an industrial railway than part of BR, however it was the location of the last two BR Class 01 shunters - hence its inclusion here.
BR took over responsibility for the Holyhead Breakwater from the Ministry of Transport in 1948, and with it the Breakwater Railway which ran the full length of the breakwater, then to the maintenance depot at the former 7ft gauge loco shed, a total distance of approximately 2 miles, and a further 1/2 mile to the Breakwater Quarries, where stone for the breakwater foundations had been obtained. The quarries had been taken over around the turn of the century (1900) by William Wild & Sons Ltd, who established a brickworks to manufacture firebricks from the silica rock. Wilds also supplied stone for breakwater maintenance.
The railway served three main purposes during the BR period:
1. Transport along the breakwater for BR personnel maintaining the breakwater and lighthouse at the seaward end, initially using a Drewry petrol railcar which was later replaced by a Wickham permanent way trolley.
2. Transport of stone from the Breakwater Quarries to maintain the breakwater foundations when required.
3. Internal shunting at the quarries and brickworks, and also transport of bricks and crushed silica down to the quay at the inland end of the breakwater for shipment by sea.
The last two operations were carried out by Wilds using a Peckett 0-4-0ST ordered by the Ministry of Transport in 1934 and supplied to Wilds as part of the contract to supply stone for the breakwater maintenance. When this loco required replacement in 1966 BR supplied (presumably under the terms of the existing contract) ED6, a departmental Fowler 0-4-0DM from the Ditton Sleeper Depot. This was found to be unreliable in service and was soon replaced by D2954 and D2955, later designated Class 01 001/002. The locos were in effect on hire to Wilds and driven by Wilds own driver, but unlike the steam loco, which was kept in a small shed at the brickworks, the diesel locos were stabled in the former 7ft gauge loco shed.

D2955 working in the quarry with an antique 'ship canal' type wooden tip wagon, September 1967.
Perhaps one of the most unusual items of rolling stock to be shunted by a BR diesel loco in commercial service.

D2955 was fitted with a length of timber below each buffer beam for use with the timber flat wagons employed for taking stone down to the breakwater

The stone was carried in three sided steel skips placed on these wagons, which were lifted off by the travelling crane on the breakwater and tipped where required

Interior of the former 7ft gauge loco shed with D2954. The standard gauge rails were carried on timber baulks supported on stone blocks within the 7ft gauge inspection pits. One of the old 7ft gauge rails still remained on the left side of the nearest pit. I doubt if D2954 was ever used in service on the Breakwater Railway, not being fitted with the timber below the buffer beams like D2955. It was certainly not used after 1971, when it was dismantled for repairs which were never completed and after that it was used as a source of spares for D2955.

The Wickham permanent way trolley used by BR workers for transport along the breakwater
The brickworks closed in 1974, but Wilds continued to supply stone for the breakwater and latterly stone was brought in by road from another of Wilds' quarries and loaded onto rail wagons near the brickworks where it could be weighed before being transported down to the breakwater. The contract with Wilds was terminated in 1975 and slate blocks were then brought in by road from Penrhyn Quarry. The blocks were transferred to rail wagons on the quay area at the inland end of the breakwater and the loco was then operated by a BR driver.

BR also provided their own wagons after 1975 - Two Conflats DB709304 and DB710155, and two flat wagon conversions (from vans ?) M 418362 and E311393

01 002 (D2955) with 01 001 (D2954) inside the shed, July 1980. The railway had last been used for stone transport the previous year, since when the stone was carried direct to where required on the breakwater by lorries. The two locos were scrapped on site in February 1982.
The reason given by staff for abandoning the railway for stone transport was the condemning of the travelling crane which ran the length of the breakwater on its own rails and was used to unload the rail wagons and place the stone where needed. It was later toppled off the breakwater and cut up on the beach at low tide. A mobile crane was later used when required.
In July 1980 the railway still showed signs of recent use by the Wickham trolley. I was told by staff in 1981 that it had been sent away in August or September 1980 for use on the Conwy Valley Line after flood damage, then taken to Bangor and scrapped. Track on the breakwater railway was lifted in late 1980 and completed by Christmas leaving just the track in the shed and a few yards outside.