Morning all, welcome to a new month! Hope everyone is keeping well, and those suffering the effects of the weather have survived without much (if any) damage.
I mentioned on the October thread that the next time I posted some info pictures, I'd take a look at the control of trains. Obviously the British system is very different from the modern day American system, and below there are two different forms of control, although both are still in use across parts of the UK. There is a commonality behind both however, in both principals and equipment. The principals of train safety remain the same, but the equipment side might be interesting for a few. British terminology is that train controllers are called signallers (dispatcher in the US) We have three, what could be termed, core safety systems, known as GSM-R, AWS and TPWS.
GSM-R is the dedicated 3G/4G railway mobile phone network which replaced an outdated radio comms network, but rather than normal phones, every train is fitted with a GSM-R unit into which the driver inserts his train identifier before starting the journey. At any time he can press one button and the system is 'intelligent' to connect him with the correct signaller that is controlling the stretch of railway he is running on. There is also a button to alert the signaller (without either needing to speak) when he's stood at a red signal, and an emergency button.
AWS (Automatic Warning System) is an old but safe system. When the train approaches a signal, it passes over a magnet. If the signal is clear, the AWS rings a bell in the cab, if the signal is at caution (double yellow/yellow aspects) or danger (red) it sounds a horn, as a secondary alert to the driver. I should add if the horn sounds, the driver has 10 seconds to cancel the auditable alert before the brakes are applied to bring the train to a stand. This system has been in use for many years, and is now supplemented by TPWS (Train Protection Warning System) which provides extra checks. It ensures that the train cannot approach a signal or junction too fast for example, again triggering a brake application if a train is deemed to be speeding. The reality is far more complicated, but that is a general overview.
For many years in the UK, semaphore signals have controlled trains over vast areas of the network. While this method of control is being phased out, it is still planned be used in some areas until 2044! In my local area, there was a location known as Barnetby, which was a Mecca for photographer - lots of freight, old signal boxes and semaphore signals. Unfortunately, they were taken out of service at Christmas 2015 and replaced by modern colour light, controlled from a centralised ops centre some 80 odd miles away.
The former manual signal box, known as Wrawby Junction, near Barnetby. This was one of the biggest manual boxes in the UK, and I believe the largest manual signal box to be single manned for the last few years of its operational life. Only one box in the UK was bigger, but that was double-manned because of the traffic volume.
The levers inside. White are unused, red control signal arms (one for each arm), yellow control distant signal arms, blue are point locks and black are point blades. The signallers used to keep these boxes spotless. In the main there were two or three staff on every 24 hours, one person covering each eight or twelve hour shift.
The box at Wrawby is seen in the distance, as a EMD-built Class 66 waits to proceed. Despite the appearance here, the train is on the second running line heading west, so the driver is looking not at the first signal that he's sat beside, but at the middle gantry. The far gantry has a signal cleared for a passenger train to proceed. Each of the three signals are controlling onward routes, Wrawby being an unusual location of having a south bound (left) line to Lincoln, a south west line (middle) to Gainsborough and west bound (right) line to Scunthorpe.
Contrast that with the modern day way of signalling, dull windowless rooms where the signallers could be hundreds of miles from the railway they are controlling!
This is one of the centres in the process of being set up near Birmingham
Instead of levers, signallers now have signalling diagrams on screens covering many miles of track, all controlled by a mouse! (Sorry this is slightly blurred). Of the screens here, the far left is an overview of the whole area, the next is our TRUST system, which tracks the location of every service operating on the UK network - this is done through location timing points rather than GPS or anything similar, then the nearest three, show the area that the signalling is currently monitoring. Much of the signalling activity is now done by a system comically known as ARS - Automatic Route Setting, which sets up routes automatically and the signallers just monitor and step in when the timetable is running late. But many staff get board with ARS on as there is nothing to do in the main, so a number of them switch it off and do the job manually.
The white lines are tracks, the red lines are trains, in the case of the nearest screen 2C40 and 2V28 designations are train identifiers that signify not a particular locomotive or train, but a service. That service (for example the 10:30 Birmingham to London) will run with the same identifier every day, allowing staff to identify the train - they are not concerned (in generally) with what rolling stock is on it.
Routes are set by clicking the red circles indicating signals. Click the one at the start of the route, and the next at the end, and the computer checks the integrity of the route (makes sure nothing will crash into something else) and then changes the relevant points and sets the signal aspect. As. you can see on the bottom right of the above screen, signals are red, green or yellow.
Hope you guys find it interesting - but do shout out if its nothing that interests anyone and I'll stop posting them! I appreciate its a very different railway/railroad scene from the US.
Rich