The station at Tanygrisiau is reached on the deviation right-of-way through this rock cutting above the Tanygrisiau reservoir. The construction of the reservoir forced the relocation of the original right-of-way and the building of the only spiral track in Britain at Dduallt. The Earl of Merioneth works her way up to the station with a typical consist of carriages. The Tanygrisiau power station building is just visible above the third carriage.