16-02-2012 Signalboxes

Hi all

Now you may have noticed in the past I have said I like signalling. I always wanted to be a signaller but after 10+ applications put in I never managed to get an interview, and so never got the job. So whenever I get to visit a signal box I always enjoy the trip.
When I was at Southern, I visited Pulborough (an old-fashioned lever semaphore box) and Three Bridges (a more modern signalling centre).
Today we did a similar thing and visited Farnham and Guildford signalling boxes.

I have attached pictures of both boxes.

Above is the panel at Farnham. This is an interesting example of a box which is part track circuited (From Alton where the line terminates to half way along the single line from Bentley and Farnham. This is shown on the bottom panel and routes are set up by pressing buttons between signals. Although the picture is blurry and with a bit of luck a colleague will send some better ones. The red lights on the panel indicate where trains are currently standing, and the white lights are where the signaller has already set a route for the train. At the moment on the panel, there is a train stood at Alton platform 1 and the route is set from Alton all the way to the end of panel on the right hand side.

The top panel is where the absolute block system starts and signals are controlled by the lever frame below. Despite the signal box having levers all the signals and points are electronically controlled and the signals are all of the colour light type. As you can just about see on the top panel, the track although absolute block does in fact still have track circuits which can indicate to the signaller where trains are. At the moment, their is a train in the reception road which had only recently shunted there.

For trains to continue to the right on that panel and head towards Aldershot's signalling area, bell codes are used between the signal boxes and only one train can travel between the boxes in each direction at one time.

While we were there S&T (signalling & telegraphs) engineers rang the box and asked the level crossing to be lowered so that they could do some work on the track circuits that are tied into that crossing. You could see the work they were doing as every now and then the track circuits would illuminate the same way they would if a train was there and then go out.

I don't think motorists were too impressed when the gates were lowered for 5 minutes while this work was carried out and then raised with no train crossing but hey ho!!

Later on and we headed down to Guildford box to see what they get up to. Again it is a bit of a poor photo and hopefully some better ones are on their way to me!

When we arrived the two signallers on duty were hard at work. A set of points at Shalford Junction (very top left of the panel) had failed and they could only get reverse detection and not the normal detection. This meant that trains from Portsmouth could not go north towards Guildford and were essentially trapped. If you were travelling in this area at about lunchtime today you may have noticed that trains were delayed by up to an hour as a result.

When we arrived, the signallers were too busy to talk to us as they were dealing with the points failure and also having to ring drivers of trains trapped and also the technicians. You could tell there were problems as a quick glance at the panel at the top left hand side of the panel showed a queue of trains all the way from Shalford Junction all the way back to where Farncombe signal box takes over!

Guidlford panel controls a much larger area then Farnham and this can be seen by the panel. The whole area from Farncombe and a bit down the North Downs line all the way to Effingham Junction and Woking and also to the border with Wokingham signal box.

While we were there they managed to fix the points failure and get normal detection. It took them nearly an hour, which shows it was a difficult fault to fix and they could trains moving again.

While we were there we managed to get a look at a real life demonstration of what we were practising yesterday on the simulator. A train phoned the signaller to report that he had had a brake demand as he passed a single yellow signal by the TPWS equipment (something that should not happen) as the driver was not at fault the signaller got him to fill out an RT3185 form which reports signalling irregularities and that signal was watched as the next train passed over it (nothing happened!)

Was a good day, and better still an early finish. Our next exam which was due on Monday has been moved forward to tomorrow as we are a day ahead so after the pub quiz I will do some revision.