Testing of the new signal No. 10 'Up Main to Exchange Inner Home' on 19th February 2012 - the first time this signal was operated from the signal box.
SIGNALLING NOTES - Chris. Hall
I am putting pen to paper as a result of a rash promise to the Editor yesterday to write this article. Since the last set of notes written in December 2008 (issue 164) quite a bit has happened - I had then to resort to 'PhotoShop' to indicate how the gantry at Kidderminster might look when we had finished our preparation for the resignalling of the main line. A real photograph (above) of the testing on 19th February 2012 when the new signal wire run was first connected and tested shows how it looks now. The new signal is currently fixed at Danger until the new works are commissioned in August 2012.
Our work is now focused on renewals and new works with the routine maintenance and a lot of the fault finding being looked after by the permanent paid staff. Parkinson's law has of course ensured that this area of work should expand to (more than) fill the resources available - the railway has embarked on some quite major work. With a gap of over three years since the last 'Signalling Notes' it will be difficult to capture the scale of the work we have done: usually successful completion just means that everything looks like it did before we started. The equipment may be renewed but functionally it is the same.
In 2009 track was being laid to provide a dock platform adjacent to platform 2 at Kidderminster and we were getting the new location cupboards equipped. Our attention was then rudely snatched away to Hampton Loade where some of our equipment had been damaged by a derailment in the September. The FPL locking bar extends some 58 feet from the signal to the point switches and this had to be renewed along with the detection extension pieces and rods and a short length of point rodding. Not the least of our problems was to transport the material to site (as train services had been curtailed). The FPL bar is a 'T' section in three lengths, joined by fishplates and supported by a dozen or so rocking arms with supports bolted to the rails. We refurbished a set of rocker arm castings and arms and manufactured and fitted a new locking bar. Temporary arrangements were made to allow trains to run on the Up and Down Main with the box switched in, the loop initially being out of service. I seem to remember that was a cold Winter.
By March 2010 the work at Hampton Loade was substantially finished and we returned to Kidderminster to reconnect the point machine in 2EL dock and commission and test the new controls. The old cable proved just too short when threaded through the new ducting and so it had to be recabled. One new small location cupboard was also built and commissioned. We then started looking at the preparatory work that would be required for the main line resignalling. The exchange line was originally laid out for shunting moves rather than running moves for passenger trains and the P-Way department had expressed the intention of relaying this line and slewing it into a straighter run and moving the pointwork in advance of the gantry much closer to the gantry. Ths would leave no space for mechanical detection of No. 18 points and have the effect of destroying much of the existing signal wire run (not something the P-Way normally do as a paperwork exercise).
The Carriage Works Sidings would now need trapping protection with the fouling point conveniently located in the middle of a three-way point, which would also need to be insulated and track-circuited. Inaccessible from the main rodding runs, the trapping would need to be operated by a point machine and the only viable solution was a set of three derailers. Somehow we needed to find six spare levers in the frame at a sensible position for the new functions they were to control. After some thought we decided to shuffle a few of the existing levers (nos. 57 to 61 to be moved one space left and nos. 47 and 50 levers to be moved to 45 and 46 respectively). This would free up levers 47 to 50 and 61 and allow use of lever 10, originally a space.
The first step was to take possession of the frame and to undertake the necessary locking alterations to allow the levers to be shuffled. We were fortunate in that the original intention to provide Locomotive Display Sidings connected to 2EL (never provided) had left us with levers 45, 46, 48 and 49 locked for this facility and therefore spare. Several weekends of work were required to make the necessary locking alterations - at this stage the locking on the new levers was omitted as this had not then been designed.
The signal wire run alongside the exchange line was renewed in a position where there would be room to slew the track and space made for an additional signal wire run from the box to the gantry. We also started work on a new location cupboard to relieve the relay room of some equipment and to allow the exchange siding to be track circuited. The electrical detection that would be required for 17 and 18 as and when the P-Way did their work (which could be done either side of the resignalling) could be housed in an existing location cupboard. A lot of this work could be carried out while trains were running which was fortunate as Winter 2010/2011 was beginning to look a bit daunting: there were several major jobs all planned to take place at the same time.
Northwood Crossing was to be upgraded to current standards and the controlling equipment, road signals and rail signals completely replaced with new equipment. To make it harder, the location cupboard contained so much equipment that it could not be removed or replaced without reducing it to its component parts and rewiring it from scratch. Sandbourne Viaduct, a good name as it was based on sandstone which we had learned in the most compelling way was not to be trifled with - once encountered during digging, we knew the hole would go no further. This viaduct was to be waterproofed, requiring us to remove and replace the signal wire run to signals 1, 3, 4 and 30 and the rodding run to and detection for points 10B. We did not undertake to replace the leaves in their original position!
Just an example of the equipment that would have to be removed and replaced to allow work on the viaduct.
Arley was also to be dug up, requiring all of our equipment from the Down Homes as far north as well clear of the North end of the platforms to be completely removed and replaced in a new position. The Arley job would be one of the biggest jobs for us of recent times and we would be unable to provide crossing facilities when trains started running again - in fact we had to ensure that we had completed enough work before allowing services to resume so that we would be able to complete the work at all before the following Winter. Just having the track in place is not enough!
The rodding run to the south end would be reinstated on the Down side where the platform was being completely rebuilt, which would allow us to specify recesses in the platform wall to accommodate the compensator bases and the lead-off bed. After a few weeks of what seemed to be a battle between us and the P-Way department where we would dig in a concrete base one weekend to find that it had been unearthed by the next, the new rodding run began to take shape. Initially, from 26th March 2011, services resumed with all trains running on the Up & Down Main with points clipped out of use but by the scheduled date of 30th April, we had reinstated crossing facilities with all equipment (except the Yard points) back in service.
Meanwhile we had disconnected and reconnected the signals and point at the south end of Bewdley South for the viaduct work and lifted the signalling cable out of the way and strapped it to the viaduct wall, out of the way of the work. The work at Bewdley and Arley had been staggered so that the start and finish dates did not coincide, to allow us to manage both jobs. Northwood Crossing had taken second place and was worked on as and when we could, and was booked off with a Handsignalman provided while the work proceeded.
Turning to more recent work, the last Winter (2011/2012) promised another challenge: it was the last opportunity to get mechanical work completed for the forthcoming resignalling. A new doll had to be lifted into position on the gantry and a new signal wire run provided. This requiried scaffolding over the main line, preventing access to the Exchange Siding for a couple of months. By now we knew sufficient to finalise the mechanical design and produce an outline of the electrical design and thus agree the fringe box electrical specification with Network Rail and their chosen contractor.
The Signal Sighting Committee with representatives from Engineering, Operating, Footplate etc. agreeing the position for the new signal.
A new doll had to be lifted into position on the gantry, into a position that had been prepared during the repaint of the gantry a few years previously. A new signal wire run was put in from the box to the gantry to control it. Mechanical locking alterations were required to the frame to provide six new levers as follows:
We had already made space for these new levers but the mechanical locking had to be manufactured, installed and tested. This work required a possession and would most easily be accommodated while the work to relay track through Bewdley tunnel was taking place. Although we work mostly at weekends, we had to resort to some mid-week activities to fit all this in. Recovering the signalling cable laid through the tunnel was a rather dispiriting task as the cable was in perfect condition but had to be removed, which would destroy it. Fortunately we were able to drag it out of the ground with an 08 shunter, concluding by dragging a dozen or so hundred yard long pieces of cable along the 'four foot' - said to be like hauling an eight coach train. We then cut it up into short sections for the rag-and-bone man to take away (cutting up wire-armoured cable is not the easiest of things to do).
Relaying the cable through the tunnel would be done by the contractor and we would be fully occupied (as we still are) with the work at Kidderminster. The P-Way department was intending to provide flat bottom CWR through the tunnel (flat bottom rail would be provided for most new work other than through stations) so we would not have to bond the rails. Contingency planning for Pilotman working was scheduled but the track circuits throughout the single line were reinstated by 1900 on the Friday before services resumed and so this was not required.
The work at Kidderminster continues with various new peices of equipment appearing on the block shelf - the latest of which (currently under test as at 16th April) is approach locking on 21 signal (the disc reading out of the Exchange Siding to the Down Main) which is one of the requirements of the new scheme. Although the only visible sign is a lamp on the block shelf that lights to show that the signal has been returned to Danger after a train has moved past it, it required an arm repeater to be fitted to this signal (which is visible from the box but will have to be proved 'off' or 'on' to allow a movement from Network Rail to take place following the resignalling).
A final reminder that this article and the photographs associated with it, as well as other S&T information, can be viewed in full colour on the unofficial S&T (signals) web site at http://www.svrsig.org/ (or look for 'svrsig' on google).