THE SIGNAL BOX

OVERSEAS

CASTLEROCK
Northern Ireland Railways

(former Belfast & Northern Counties Railway)

by Simon Lowe

Castlerock signal box
Photograph by Simon Lowe, 1/5/00

Castlerock can now claim the distinction of being the last regularly staffed mechanical signal box in Northern Ireland. It controls a crossing loop and level crossing on the single line from Belfast to Derry/Londonderry. The up starting signal, a lovely example of a somersault signal, is visible in this picture. All the surviving semaphores on the NIR system are of the somersault pattern.

The signal box is of simple prefabricated construction, provided here during the nineteen-seventies. It was apparently intended only as a temporary installation.

Signal box diagram at Castlerock
Photograph by Simon Lowe, 1/5/00
(Click on the diagram to view a larger scale image)

The signal box diagram is drawn to a very early style, as witnessed by the way that the points have been depicted.

Interior of Castlerock box
Photograph by Simon Lowe, 1/5/00

There is a 10-lever Railway Signal Company frame inside, installed here second-hand. The loop points have economical FPLs, hence levers 5 and 6 are painted half blue and half black. The distant signal levers are painted yellow in accordance with standard practice throughout the UK. The distant signals at Castlerock, however, are no longer worked.

Token instrument at Castlerock
Photograph by Simon Lowe, 1/5/00
Tablet instrument at castlerock
Photograph by Simon Lowe, 1/5/00


Manson's token exchanger apparatus at Castlerock
Photograph by Simon Lowe, 1/5/00

The section to Londonderry is worked by key token (above left), the instrument seen here being unusually painted green. The key tokens themselves were given very small handles so as to minimise their weight for use with token exchange apparatus. Because the handles are not large enough to the bear the name of the section in full, they are simply stamped 'CK'/'LY'. The key token circuit to Derry operates over radio channels.

The single line section to Coleraine is worked by Tyer's No.6 tablet (above right). One of the key tokens for the Derry section can be seen resting on top of the tablet instrument. The leather pouch has clearly seen better days.

A Manson's token exchanger (right) still stands at the Derry end of the down platform, although its detachable exchanging head has been taken away. The down starting signal, number 4, is visible a few yards in advance.



Comments about this article should be addressed to Simon Lowe