Welcome to the April update of Forgotten Relics.

We return to a record breaker this month: the 667-yard Torpantau Tunnel which plots a curved course through the magnificent Brecon Beacons. Hosting summit level on the Breakneck & Murder Railway - otherwise known as the Brecon & Merthyr - it was the highest tunnel on the UK network until claimed by closure in 1964.

Auchendinny Tunnel is, in contrast, acutely workaday. It pushed the Penicuik Railway through a rocky spur on the bank of the River North Esk. Today its fine curves host a popular cycle path but former railway furniture - substantial insulated brackets for the telegraph wires - doff their caps to the bore's intended role.

Parkhead Viaduct is slowly sinking. Originally built in timber due to poor ground conditions, it was later encased in brick to make it more stable. However its decline continued such that track level ended up around three feet higher than the top of its parapets. The brickwork is tied together by an assortment of plates and bars but that hasn’t prevented one spandrel from bulging more than any I have ever seen.

Facing a more upright future is the old signal box at Bendor Crossing on the NER’s former Cornhill branch. Decaying until recently, the neat little structure has now been transformed into a comfy dwelling. It sits very happily in the Northumberland landscape.

Queensbury Tunnel could yet be edited from the landscape of West Yorkshire, depending on which way the Highways Agency choose to go with its remedial works. Back in 1878, a few months before its opening, an intrepid reporter put his best foot forward to record the goings-on at each of its shafts. The result was a two-part story, providing a unique insight into the trials and tribulations of Victorian tunnel construction.