SVR S&T Dept.
SIGNALLING NOTES - Chris. Hall
We suddenly found ourselves rather busy so I thought it was time to record our activities once more. We have finished prepatory work on the new ground frame for Foley Park and now have in stock a replacement Down Starting Signal for Highley and a refurbished ground signal for Bridgnorth Yard as well as many refurbished cranks and other equipment.
A report from the routine maintenance team came in that the head of the ¾″ BSW bolt that secured the extension piece to the normally open switch rail of the south end points at Highley had sheared off. We reviewed the history of these points: we had inherited them from British Rail and the normally open switch was still in good condition after more than fifty years’ use (forty five of these under SVR) and would probably last for another fifty years. The normally closed switch had been identified the previous year as sufficiently worn to require replacement and had been replaced a few months back. We had recut the FPL stretcher over twenty years ago to allow the points to be bolted reverse but that had been done in situ when the disc signal for movements into the Yard had been installed and the locking modified. This meant that the extension piece on the normally open switch had probably not been disturbed for over fifty years. (Adjustment of the detection is effected elsewhere.) It was unlikely to develop a sudden urge to move and would be retained by the bolt stub anyway.
This prompted a visit on 8 September to remove the stub of the ¾″ bolt and fit a new bolt. To do this we would need to split the switches between trains, remove the extension piece and FPL stretcher, undo the bolt stub and fit a new bolt. We approached this job armed with our normal optimism and made arrangements with the signalman for a brief disconnection of the points. The locking bar had just about been making contact with the bolt head when the points were bolted reverse and so we had brought a petrol generator and hand grinder to give it a trim, taking about an inch off its length. Before the extension piece could be removed, the stretchers would need to be undone from one switch, the 1⅛″ bolt securing the FPL stretcher undone and the two switches opened out so that each switch was up against its stock rail. The easiest way to achieve this was to clip one switch normal and to use the efforts of the signalman to reverse the other switch. The relevant signals were booked off and the services of a handsignalman obtained just in case the job took longer than a few minutes.
We hoped to dislodge the extension piece by lifting it off the switch with a crowbar but it behaved as if it was welded in place. Although we had undone the 1⅛″ bolt, we could not move that in the switch either. After lunch we were reinvigorated and attacked the extension piece with a large lump hammer and several trains later were able to separate it from the switch blade. There was about an inch of threaded bolt protruding from the switch and our efforts with 18″ and 36″ stilsons only suceeded in shaving metal from the stub. Hammering the other bolt vigorously proved completely unable to move it. We concluded that heat was required so were reassembled the equipment, adjusted the switch detection to cope with the slight distortion of the extension piece, tested it, booked the signals back on and retired at 4 p.m. having achieved nothing.
Occasional problems with clearing the Down Home signal had been reported so on our next visit on 15 September we made some further adjustments to the open switch detection. We were fortunate to find the Bridgnorth P-Way team on site and asked to borrow their heating pipes. They readily cooperated and provided access to their equipment as well as lending us their trolley for us to transport our petrol generator and other equipment to the work site. Another day of disconnections saw a little more success. After an hour or two of heating and struggling to get a purchase on the bolt stub, with Stilsons and Mole wrench we had succeeded in moving the bolt through about 30° back and forth. The bolt stub was now an interesting shape but our optimism was such that we thought that with a little more heating it would rotate a full half turn and then undo. The optimism evaporated and we turned our attention to the larger bolt. After hitting it as hard as we could for nearly an hour, the bolt finally started to move allowing us to remove it and fit a brand new bolt.
The bolt stub had resisted all our efforts so we reassembled the equipment, restored normal working and postponed further work until after the Gala.
The next weekend was Gala weekend so we planned an indoor job out of the way on the Sunday although we would be on call that day for any faults. The first indication that things would not turn out this way was a text message received at 16:21 on the Saturday via one of our colleagues on holiday in Switzerland that a crank on the south end points at Hampton Loade had seized trapping two trains there with the south end points standing reverse and unable to be put normal. We had provided S&T cover for the gala weekend during day hours but with no faults reported by about 3.30 pm, the cover had been stood down. Unfortunate timing as it turned out but Chris Thomas was available at Hampton Loade and was able to investigate with remote S&T assistance from a parked car half way between Bewdley and Cardiff. The little-used siding at Hampton Loade had been pressed into service for the gala and two days of unaccustomed and frequent use had caused the lead off crank for the siding points to lift just enough to foul a crank pin on the crank for the south end points, forming a very solid obstruction. The crank was gently pressed down and normal working resumed with only about a 30 minute delay.
I can only describe a somewhat remote perspective as I was travelling back from Birmingham to Bridgnorth and was congratulating myself on completing my meeting by 3.35pm so that I could catch the 5.5pm departure from Kidderminster and arrive punctually for an appointment at Bridgnorth at 6.45pm. I realised things were not going well when our train had not moved and recalled that my mobile phone had bleeped earlier. I announced my presence and was told that I would be met at Bewdley. I spoke to the Duty Officer there and was told that I should alight at Hampton Loade. By the time I got to Highley the fault had been cleared. I had offered every assistance short of actual help and I was told my services would not now be required. I was grateful for my punctual arrival at Bridgnorth, the train itself being only 30 minutes late.
On the Saturday night further delays occurred due to a problem with the reverser on 1450 hauling the 7.50pm non-stop (so called) from Bridgnorth to Kidderminster, which eventually arrived about 90 minutes late. The Up Starting signal at Arley failed at about 10 pm that night which made it clear that Sunday would be an excursion into the country calling at Arley to investigate and then to examine the problem at Hampton Loade at first hand.
Sunday proved to be an excellent day. I abandoned my car at Bridgnorth where I had left it on the Friday evening after working Bewdley South and boarded the 7.22 am departure to travel to work in style with an superb restaurant car breakfast. I travelled back to Bewdley on this train with Tony, who had breakfasted at Kidderminster in case parking at Bewdley had been full. We worked out our plan: assemble the necessary equipment (test meter, spare fuses, screwdriver and pliers) and take advantage of the local service to Arley which should give us about twenty minutes when we would be able to test the Up Starting Signal with the section empty and the Down train refused. Some quick fault finding with the meter showed that the catch handle contacts were not making up so we lifted the floor plate, removed some dog hairs and other debris and cleaned the motion. We were able to board the next Down train with the equipment restored to normal working.
At Hampton Loade the lead off cranks are mounted on crossing timbers secured to concrete bases and sit below removable decking. The lead off crank base for the siding points had worked loose and the crank was rising as the points were placed normal. A pin on the accommodating crank for the south end points had come into contact with it. A short term fix was to fit a specially made-to-measure ‘top hat’ pin with a thin flat head so that clearance would be increased. We were then able to retire to the Up Platform for a lunch of sandwiches, tea and home-made cake.
Returning to Bewdley we concluded the day by making the special pin. We also found a suitable washer in case the pin did not fit and it was possible to pack the existing pin using the washer to lift it out of the way. I rounded off the weekend with a turn at Kidderminster on the Monday with a trainee to do all my work for me.
On 29 September we assembled a bit more equipment and personnel, adding a magnetic drill, a cutting disc for the hand grinder, extension leads, more petrol for the generator, a pipe wrench, drills, ½″ and ⅝″ taps and bolts. Another day of disconnection that should see the job resolved one way or another. After another hour of fruitless efforts with the Stilsons and a pipe wrench we were able to conclude that the bolt stub was firmly seized in the switch rail. This left us no alternative but to grind the stub off, flush with the switch. This left nothing to retain the extension piece in place except a single bolt. We were now committed: unless we could drill and tap a hole in the bolt, we would have to clip the points normal and take them out of use until the switch could be replaced.
One thing in our favour was that regulations at Highley meant that we could continue working right up until the arrival of a train at the respective Home signal before having to reassemble the points to admit the train into the station. A strange feature of this regulation (restricted clearance) is that the signalmen are aware when it is being applied (it is a statutory ‘method of working’ that is a mandatory requirement) but the Drivers no longer want to know it is being applied (and there is a derogation to this effect in statutory guidance). We are assured that they are now eternally vigilant.
With power from a portable generator, we found the magnetic drill could not get sufficient adhesion on the extension piece to remain in place to drill the first hole. We had to resort to a 110V hand drill and selected a nice sharp drill. Delays to trains would now be inevitable. This was a careful and slow operation as if we broke the drill bit we would have to leave the signals disconnected until the switch was replaced. Fortunately we succeeded and were able to open out the hole in stages to 9.8mm, the largest parallel shank drill we had that would fit the hand drill. This was a little short of the recommended tapping size for ½″ BSW, which was 13/32″. We had a mathematician on hand to calculate we were 20thou short. The hole was just large enough for the tap to enter the hole and we were able to cut a few threads before the tap got so tight that we were worried it might break, despite it being made in Britain rather than a Chinese import.
Discretion was the better part of valour. After sixty years of corrosion and some vicious heat treatment a fortnight earlier, the material of the bolt stub was rather hard. We were able to use the magnetic drill and the morse taper drill bit we had brought to open out the hole to 13/32″. We heard an Up train whistle several times at the Up Home signal before we were ready to reassemble the points and allow the signalman to restore the point lever and admit the train.
Now it was just a matter of tapping the hole right through the bolt, using a tap and a small adjustable spanner, without breaking the tap. The 3.20pm from Kidderminster was held at the Down Home for 5 minutes while we completed the work and were able to fit a ½″ bolt, reassembling the points so that it could proceed. With the job finished, all we had to do was gauge the FPL, adjust the detection, return the point clip and our borrowed equipment and carry everything back to the platform to board the next up train.
Grateful thanks are due to the station workshop for the loan of a 110V hand drill, a 5.5mm hexagon bit and socket set. This job helped me to realise that we are all getting older and would desperately like to pass our expertise onto younger members of the Department, something we are currently unable to do as we have not been able to attract younger volunteers. I suppose it is no use saying that the job is varied and interesting.
On 20 October a lineside location cupboard at Bewdley North was replaced between trains after three man days of prepatory work. It all worked correctly.
The precise location of the ground frame at Foley Park is now becoming a matter that must be resolved as it affects our preparation for the work - where the concrete plinth will be sited, what cable lengths we need etc. The current status of the design is shown on the next page. Our Winter work will therefore include renewal of the lead off cranks at Hampton Loade and the large amount of work associated with the Foley Park Siding and Falling Sands Viaduct work.
A reminder that this article, as well as other information on Signal Engineering, can be viewed in full colour here on the unofficial Signal Engineering web site.
© OpenStreetMap contributors. An artist's impression of the new ground frame at Foley Park looking South from the running line with point rodding running West to the 'B' end of the points. Below is a map showing Falling Sanda Viaduct and the position of the new sidings. [Diagram: author]