Stafford Signal Box Visits
Wednesday 30th July and Wednesday 19th November 2014

Stafford No.4 box is south of the station to the east and Stafford No.5 is north to the west. They are two of the busiest remaining NR mechanical boxes. Both survived, with others north of Nuneaton, as a result of the cost over-run of the original 1960s WCML electrification project, but gradually most have been abolished. They are an island in a power signalled area, interfacing Wolverhampton PSB in the Birmingham direction and Stoke-on- Trent Signalling Control Centre on both the Trent Valley line south (Colwich workstation) and the WCML to the north (Norton Bridge workstation).

Stafford No.4 is a 1960 BR London Midland Region (LMR) standard box built when signalling was being rationalised ready for the WCML electrification. It has large windows, a very bright airy and agreeable interior during the day with a central 'bay' window. It is the busier of the two boxes, controlling the Birmingham line junction and that line to Penkridge; as well as the Trent Valley line to beyond Whitehouse Jct. where the slow lines converge, one at a time, with the fast lines. The 105 lever BR (LMR) frame is at the rear of the box; less than 10 levers are white (spare) with just a few removed. All except two points are electrically worked; all main running signals are colour lights, with some remaining mechanically worked ground disc shunt signals. There are no yellow (distant signal) levers in either box, as the four aspect signals automatically display restricted aspects before a red or single yellow. It is open 24 hours and operated by two Grade 7 signallers (one on Sunday nights) reflecting the complex working.

Stafford No.5 is an unusually austere 1952 brick-built design. Inside, an extremely long BR (LMR) frame of 150 levers at the rear of the box is housed in a rather thin and spartan operating floor. Much of the central part of the frame is OOU, (about 70 spare levers and 10 removed) with the closure of the former lines to Wellington (L&NWR) and Uttoxeter (GNR). It is also Grade 7, but single manned; with levers in use at each end the signaller walks miles each shift and rarely stops!

Unusually, the signallers in both boxes use a system of 'slots' to control the lines between them. This has some operational similarities to both absolute block and direction lever working, but Track Circuit Block (TCB) rules apply to all lines. It is similar both ways, with No.4 box giving slots to No.5 for Up, and No.5 box giving slots to No.4 for Down trains. For a Down train, No.4 requests a slot for the appropriate route from No.5 by entering the train headcode into the 'OFFERED TO No.5' field (or berth) on the VDU train describer in No.4 box. This headcode displays in the 'OFFERED FROM No.4' field of the train describer in No.5 box which alerts the signaller that a slot is required. If the train can be accepted, the No.5 signaller pulls the appropriate red slot lever illuminating a block shelf light in No.4 box to indicate 'slot given'. This allows the protecting signal to clear once No.4 has cleared its starting signal. Separate slot levers are provided for the main and calling-on signals of the 'sending' box.

A similar process operates in the opposite direction for Up trains. This all sounds rather complex, but the signallers have good visibility of trains approaching on all routes from their train describers, TRUST screens and the CCF (Control Centre of the Future) visual display route maps. Of the eight lines between the boxes, only two (P6 and the very recently temporarily closed Up & Down Goods through the former Royal Mail terminal 'P7') have full bi-directional working with main aspect signals. A scheme to allow main aspect signal access to P1 from the south was apparently installed in the 1990s but never commissioned. Each train has its own booked platform or through road, so in times of normal operation, trains can be signalled with little or no telephone contact between the boxes. Other aspects of TCB which simplify the job, compared to many mechanical boxes, are that there are no train registers to complete or requirement for tail lamps to be checked. Both boxes are due to close later this year (they are expected to be demolished) with control transferred to the £17M Rugby ROC (Rail Operating Centre) which will eventually control the WCML (south) and branches.