Plas Tan-y-bwlch was the home of the Oakeley family, through whose estate several miles of railway passed. It is an ancient 15th century manor house rebuilt in 18th/19th century as the seat of the Oakeley family, quarry owners at Dinas until 1961.
FRM No.68 (Spring 1975) reported - "Since the death of Mrs Inge (the last of the [Oakeley] family) 13 years ago, the Oakeley mansion Plas Tan-y-Bwlch has been in semi-limbo. On the disposal of the estate it was bought by the Bibby shipping concern as a country club, and Plas Halt opened specially on the FR; but National Park planners clipped the Bibby wings and after some time the constituent counties of what was to become Gwynedd bought the Plas for conversion into the Snowdonia National Park Centre, a study centre for those wanting to learn more about this unique district. After a very long and expensive spell of repairs .... the Plas at last opened its doors fully this year with residential courses ...."
The house remains a residential Environmental Studies Centre, administered by the National Park Authority. It is below the FR line at Milestone Curve/Tyler's Curve.