SVR S&T Dept.
http://www.svrsig.org/svr/Iss195.htm

S & T Notes - issue 196

SIGNALLING NOTES - Chris. Hall

SIGNALLING NOTES - Chris. Hall

Normally my prompt to write this article is the sound of the previous issue hitting the doormat but issue 195 was in such good time that I nearly forgot! We have been quite busy since July as we have had about nine worn cranks to refurbish (ex Bridgnorth) as well as our normal workload.

Just before ‘Scotsman week’ we had a fault on the Up Starting Signal at Bewdley South - the arm repeater was showing ‘wrong’. Not a huge problem you might think, because by craning your neck out of the signal box window you can just about see the signal arm but arm proving is in the single line controls as clearing the signal is the sole authority to enter the single line section. Pilotman working was therefore instituted. The fault turned out to be a broken wire in the 5-core cable from the location cabinet to the top of the signal for which a temporary repair was effected within a few hours, tested and normal working resumed. The following weekend the cable from the location cabinet back to the box failed for the same function (the original fault may have made that core of the cable susceptible to lightening but we'll never know). This cable had been disturbed for the work on the bypass bridge some time ago and had been excavated again a few years ago for work on the viaduct (not disconnected, just tied out of the way this time). Another repair was effected (it’s no good saying it was a new fault, noone believes that) using a spare core. We had now attracted attention and were asked to provide assurance that the fault would not recur during Scotsman week. Our crystal ball was out of order but we intended to provide ‘on call’ Signal Engineering cover for the week anyway including extended hours but no engineering problems were encountered throughout the 6 days.

There are a few other cables that have been disturbed for major engineering work, dragged clear and then reinstated after the work: from the Up Starting Signal at Highley to the box; from the end of Northwood Lane to just north of the Elan Valley Aqeduct at Trimpley; across the bypass bridge at Bridgnorth and from the Down Outer Advanced Starting Signal to the Up Homes at Kidderminster. We will need to replace the last of these as part of the potential P-Way Depot being considered at Foley Park as some extra controls will be required if this work goes ahead and there are now no spare cores in this cable. All of these cables are on borrowed time, expenditure for cable replacement having been deferred.

First I'll have a look at our planned work for the months ahead: one of the switches recovered from Arley will be installed by the P-Way to replace the normally-closed switch on 12 points at Bridgnorth (which, we are told, has been run through again) so we are ordering a replacement insulated GW-style FPL stretcher as we have none currently in stock (it will have to be specially made for us) and the existing stretcher cannot be reused - the S&T side of this work will not be easy or quick and so the Down Home signals will have to be taken out of use from the P-Way work until completion. A possession is being booked to scaffold the Bewdley North Up Inner Homes bracket signal for essential engineering work - this will block the running lines and so will have to take place in January/February. The ex-Radyr bracket signal in the car park at Kidderminster will need to be refurbished to replace the (temporary) Platform 1 Starting Signal that has been there for the last 32 years - this work is supported by the South East Branch of the SVRA. The planned track relaying north of Hampton Loade will require us to protect or remove our signalling cable there. The compensation on the rodding run from the signal box to the south end of Bridgnorth will have to be relocated, requiring the south end pointwork to be booked off for a few weeks in January/February (anyone who likes digging frozen ballast is welcome to join us for this job).

So what have we been doing with ourselves through the Summer? Routine maintenance and testing is up to date. A relay tester, based on a design used by the Mid Hants Railway and adapted for our own purposes has been developed. We are hoping to bring routine testing of relays ‘in-house’ to avoid external costs. The former ‘T-pole’ location cupboard on platform 1 at Bridgnorth has been moved and renewed in order to be clear of development work at the Station.

The Down Homes at Arley have been scaffolded to allow the signal to be repainted, the signal arms refurbished and the access platform timbers renewed. This can be done in the running season as the scaffold is clear of the line. As I write this article the front timber has been removed to allow better access for painting.

We have replaced some more cranks at Bridgnorth, the lead-off to the north end pointwork this time. The drive crank to 12 points, where the drive is taken from the rodding to the PWay stretcher on the points, was also to be replaced - this would require disconnection of the relevant signals as the points would be completely free of any interlocking and passenger trains would still need to use them. We did this without any delay to traffic, there being a convenient Trainee in the box who could provide support as Handsignalman.

Six of the nine cranks that have been recovered from Bridgnorth have been machined and refurbished - this is slow and time consuming work as we have to machine the two-inch diameter main pivot pin so that we can sleeve it to take a crank that has been milled out to suit (we had to make a boring tool for the milling machine as part of this work). Each crank is about a day’s work (which is, of course, free of labour costs) but it would cost several hundred pounds to get a new casting.

We have fitted out the 'Mezzanine' floor in our storage shed at Kidderminster to accommodate electrical fittings - this building is a significant step forward for protecting newly refurbished equipment. The switching out box (lamps on/off/box closed) at Kidderminster has been repaired after use by a heavy-handed signalman caused it to fail.

An unusual fault - a bolt dropped out of the point rodding at Hampton Loade - caused us to be diverted from Bridgnorth to Hampton Loade where a speedy repair was effected.

A final reminder that this article, as well as other information on Signal Engineering, can be viewed in full colour on the unofficial Signal Engineering web site.

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