THE SIGNAL BOX

PHOTO GALLERY

Rhymney Railway

YSTRAD MYNACH SOUTH

Opened: c1890

Closed: ——

Location code: W76/03


Ystrad Mynach South signal boxYstrad Mynach South, north of Caerphilly on the Rhymney Railway's main route to Nantybwch, was built part-way up the embankment to afford the signalman a panoramic view of the sweeping curve of the main line, and of the Merthyr branch that diverged here.

The box was built by McKenzie & Holland to their standard design that was produced between 1875 and 1921, although most examples on the Rhymney Railway were built in stone rather than the more usual use of brick (as at Bargoed Pits) or timber.

Note how the rodding connections to the points are brought down to ground level via a specially built platform and cranks.


Interior of Ystrad Mynach South box Originally, the layout at Ystrad Mynach South would have been controlled from a McKenzie & Holland lever frame similar to that at Caerphilly East, but that was replaced by the Great Western Railway by a forty-five lever frame of their standard pattern built from around 1926 known as the 5-bar Vertical Tappet type.

Along the front of the block shelf are an interesting mixture of new and old fittings. There are modern white plastic-case signal repeaters mixed amongst the traditional black-cased variety, and Welwyn Control releases for the block instruments. On the shelf, between the two post-1947 block instruments, are a pair of closing switches which are connected by a steel bar (difficult to see in the photograph) which ensures they work simultaneously. This clumsy method was commonly used on the GW where it was necessary to have more electrical contacts than were available in the standard closing switch.

Above the instruments is the plan of the track layout.



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All photographs copyright © John Hinson unless otherwise stated