Power Signalling At Bristol
All location cases are the welded steel type having two half doors on the front of the case with three point locking. The cases are made in three standard sizes, 3 ft. 6 in., 4 ft. 9 in., and 6 ft. 3 in. high, the depth in each case being 1 ft 3 in. and the width 2 ft. 11 in. inside dimensions.
With the doors in the locked position, suitable arrangements have been made for padlocking. A link is also used for automatically holding each door in the fully open position. The hinges and hinge pins are made of brass. The removable tops of the case are constructed to allow the free circulation of air while at the same time preventing the ingress of driving rain and are made in triangular form to drain off moisture. At the back inside corners of the case running from top to bottom are slotted angle irons upon which brackets supporting the shelves are fixed. This permits the shelves being arranged in any convenient position.
Pine wood shelves and backboards 1 in. thick finished with two coats of shellac varnish are used.
A standardised arrangement of apparatus has been used. Relays and track feed sets being mounted on shelves or backboards in the top half of the box, the bottom half being used for fixing the pot ends for the lead covered cables running between the location and the cabin.
Immediately in front of the pot ends ire vertical battens to which are fixed terminal blocks, the tails from the pot ends being fixed to the terminal blocks. Thus a distinct line of demarcation is made between the main line cables and the wire from the functions to the location box.
The cases are painted with one coat of anti-corrosive priming, one coat ferro-graphite paint and a final coat of durable green enamel, the interiors having a final coat of grey. The outsides of the cases present a neat appearance and in accordance with modern tendencies are devoid of all mouldings. An aluminium nameplate engraved with the location case number is fitted on the door. The cases are mounted on concrete foundations having troughs cut to receive the trunking.
By using large type welded steel cases, all the apparatus at a location can be neatly arranged within one housing increasing the facility for maintenance and clearing the permanent way of unnecessary fittings.