Well Well Well

There are no boring days on the tube, but some animals are more equal than others :P So:

I arrived at ROV to a very pleasant surprise. For once, on a Friday morning, I was actually early to class, despite having left at about the same time. The reason for this will become clear when I tell you what was being shown on the destination indicator for platform 1 (services via WOO):

1. Northolt 4 mins
2. Woodford 6 mins

I also happened to notice the following trains indicated on platform 2 (services via HAI):

1. Hainault 3 mins
2. Hainault 7 mins

This second HAI service was a through train from central London and I managed to spot it in eastbound platform 3 at WOO, showing Hainault via Woodford. Why those two through trains were routed over the WOO-HAI section at that time (about 10:00) on a Friday I have no idea, but it was a very pleasant surprise. I almost felt as if it was simply to confirm my weekend post :P

Having seen one rare train (well, a perfectly ordinary train working a rare service), I was in for another small treat courtesy of the Central line. I noticed, as we were sat in westbound platform 1 at SNA (Snaresbrook) that the next train due was not in service. However, the train which passed us in the other direction, as we approached LES (Leytonstone), looked like it was showing Epping (EPP) (it's hard to tell at speed, the text is not very big on the front of the 1992 stock) and looked very much in service. I suspected that the train which was not in service had been held. Sure enough, we began to slow down on the approach to LES and the signal controlling access to LES (LES 5760) was indicating that we would be routed into westbound platform 1. As I've mentioned before, on the Central line, junctions are controlled by junction signals, which display an arrow pointing in the direction of whichever route is set (on most railways, only a divergent route will be indicated and, also, three single lamps arranged in a line are used instead of an arrow on an LED display.) Given below is a drawing of such a signal (sc. the type used on the Central line), showing a "proceed" (green) aspect and indicating that a route diverging to the left is set:

A drawing of a junction signal on the Central line. This signal is showing a green aspect, but it can also display white or red. The junction indicator indicates the route to the left is set

Below is a photograph of an actual such signal. The signal is actually LES 5761, unless I'm much mistaken, and is the starting signal at LES eastbound platform 3. It is indicating that the train is cleared on towards WAN (Wanstead):

A junction signal at Leytonstone showing a green aspect. The junction indicator indicates the route to the left is set. (Cropped from an image courtesy Matthew Black (via Wikipedia))

Were the train in question cleared towards SNA, the arrow would be pointing straight on.

This is to be contrasted with the more traditional junction signal, which looks like this:

A diagram of an old style signal with junction indicator

A signal controlling Hanger Lane junction on the District and Piccadilly lines showing a proceed aspect with junction indicator lit. This indicates that the route to the left (towards Ealing Broadway on the District line) is cleared. Note that if the indicator were not lit, this would indicate that the straight route towards North Ealing on the Piccadilly line was cleared). (Image courtesy http://www.districtdave.co.uk/html/signalling.html)

So, anyway, in this case LES 5760 (the one controlling access to the platforms at LES from the EPP branch) was showing an arrow pointing to the left (visible from the carriage in certain places), indicating that we were cleared into westbound platform 1.

I'm sure I'll go into more detail about LES, but for now, I will just give you a diagram of the track layout. I'm pretty much certain it's still like this, but I don't have any footage of the track taken since the work was done so perhaps there're some small differences?:

A schematic diagram of the track layout around LES. The signal in question (LES 5760) is highlighted by showing green in this diagram

For reasons of straight simplicity, it is most common for trains from WAN to use WB1 and for trains from SNA to use WB2. However, both platforms are available from both WAN and SNA by the scissors crossover (the crossover just to the right of LES 5760 that looks like an X). This made me think that the not in service train was, indeed, still in WB2 at LES and, sure enough, the RAT was sitting in WB2 when we pulled into WB1. As we came to a stop, it got on its way, heading up towards EPP.

After that it was an uneventful journey into LIS (Liverpool Street) and, as I had expected, it's much smoother heading out of WB1 than WB2 - much more comfortable where the tracks merge.

At LIS I got onto a Hammersmith & City line train to Hammersmith and all was going well until we reached Farringdon. We stopped and I noticed the doors hadn't opened, which was when I glanced towards the front of the carriage to see that the most of the front doors were beyond the gate at the end of the platform - a minor overshoot. On a number of lines this would have probably been a small big deal, I think. Happily, however, we were on an S7 and, as you may remember, S7s have selective door operation for the platforms which (unlike the nice, roomy one at Farringdon) are not long enough. I understand that at these platforms, the CSDE equipment (more on this soon) checks that the train is correctly berthed and then enables only the doors which are adjacent to the platform (and none which are not fully within the limits of the platform) to open. It's come to my attention that the S Stock trains use a new track-mounted position detector, which is different to the old-fashioned CSDE loops, but the principles and functions must surely be about the same. It may even be called CSDE equipment. Anyway, by whichever means, only the appropriate doors in the front and/or rear carriages will not open at short stations. Sometimes this is quite a few, as at Baker Street, sometimes it's only one or two. At Farringdon, though, all of the doors will usually open. So, what would have happened on our incorrectly berthed train is: the CSDE (or equivalent equipment) would have found that the train was not correctly berthed and would not have allowed the doors to be opened as normal. This is because that would allow a set of doors which was not fully within the platform to open, which could be a safety risk (people ending up on the track, that sort of thing.) In this case, actually, the train was simply beyond the gate, but there was still a bit of platform there. Even so, London Underground does not have the safety record it does without fail-safes. So, as per procedure, the T/Op opened his cab door, got out on to the platform, visually confirmed which doors were adjacent to the platform, confirmed that it was safe to open them and opened the doors in all carriages but the first (cue one person hurrying back to the second carriage when the message played informing that the doors in the first carriage would not open). The T/Op then closed up, checked all the doors were closed, got back in his cab and we were away. Whether the choice of doors which are left closed and the ability to open any doors is affected by the new equipment, I don't know, but I am certain that all doors usually open at Farringdon, that we had overshot by a small amount and that the T/Op left his cab. No problems, of course, just something new for me. I guess our T/Op was slightly new to the S7s because as we approached King's X we were held at a red signal and, as we were trying to get on our way, the train rolled back before the T/Op caught it and proceeded on to King's X. Quite an experience, actually, realising your train is going backwards :P

CSDE

So, CSDE. CSDE (Correct Side Door Enable) is a handy bit of kit that, as with all things London Underground, does what it says on the tin. It makes sure that the doors can only open on the correct side of the train (so that they're not opened on the wrong side by mistake) and that they can only be opened if the train is properly berthed. It's also the bit of kit controlling SDO (Selective Door Operation) as well, as we saw above. It's a simple loop that sends a signal to a bit of equipment on the train - it's pretty straightforward. If the station is closed or if the train is not correctly berthed, the doors can't be opened. If the train's in the right place, they can - but only on the correct side. Simple. The new S Stock equipment does pretty much the same job with a small bit of track-mounted kit - rather than a loop - and is presumably involved in the fancy SDO now required.

In some situations, though, it's necessary to override this piece of equipment, for example if there's a fault, or if there's been an overshoot on a train without SDO. (In some cases it would be necessary to continue to the next station, or obtain permission to "set back", where the train is driven back into the platform from the rear cab.) This can be done with the Door Enable Override, which allows the doors to be opened on either side. This is obviously potentially dangerous, though, so the T/Op is supposed to make sure that the station is open (generally it's obvious if it's not), operate the door enable override, open the cab door, put one foot on the platform to make sure they're about to open the doors on the correct side and then open the doors. Certainly this is the old procedure and I've no reason to imagine anything has changed on the S stocks.

This might seem like overkill, but actually the following blog post from a great blog by a Central line driver should give you an idea why:

http://aslefshrugged.blogspot.co.uk/2013/06/a-reasonably-uneventful-week-highlight.html

You can read the full story there, but - in this case - aslefshrugged mistakenly opened the doors on the wrong side. Obviously he quickly closed them, opened the doors on the right side, made a PA requesting passengers to pull a handle (pull one of the passenger emergency alarms) if anybody had fallen out and then informed Wood Lane (the control room) of what had happened. The next train came through nice and slowly checking there was nobody on the tracks and aslefshrugged was taken off at the next depot and given an alcohol and drugs test. Happily, nobody was harmed, but this is why convoluted procedures are still used. aslefshrugged is an experienced, careful and (from reading his blog) very good T/Op - it's too easy to press the wrong button by mistake (e.g. I'm sure I'll find many typos when I check this post at the end :P).

So, anyway, we eventually made Euston Square without further problems and it was shaping up to be a fairly normal ride home - although I did again spot a C stock Circle line train in Moorgate platform 3 (I think it was 3, might've been 4). (See previous posts for why that's fairly noteworthy :P) I got a Loughton (LOU) train at LIS and everything was going well until we reached STR (Stratford). As we were sitting there, sonia came over with "this is a Central line train to Leytonstone." The T/Op then informed us that, due to late running, the train would now be terminating at LES. We were advised to change at LEY (Leyton). This is a good move because trains terminating at LES will generally (unless something really interesting's going on :P) use WB2 (see the diagram). As you'll notice, you then have to cross over (in this case, going down and alongside the ticket hall) to EB3 to continue eastbound. At LEY, of course, you just get out and wait on the same platform. I, however, wasn't that fussed about catching the HAI via NEP train behind us, I haven't been into WB2 from central London in a long while and, to be honest, in the event of any problems, LES is a much better place to be stuck than LEY. So I stayed on the  train, but was sure to make my way to the back to make the change easier at LES.

So we pulled into WB2 and I set off - having enjoyed going over the crossover for a change - for EB3. I'd expected that the train I'd just left would be taken back out WB pretty quickly and was expecting it to be a pretty speedy, straightforward reverse. Indeed some people were boarding the train as I left. However, I noticed that it was being closed up and then we were informed over the PA that the train on platform 2 was out of service. Apparently it wasn't heading back into central London for a little while (hence it was closed up so that people would get on the train on WB1 and not waste time sitting in a train that wasn't going anywhere soon.) So here's what I think must have happened. I believe there are limits regarding how long a person can drive a train without a break and also without a meal; but I'm not really sure how much that would have had to do with it. One is entitled to overtime, though, if one is forced to work overtime when stuck somewhere and paying it is not something London Underground are that keen on. So, I imagine, the T/Op driving my train was probably stuck somewhere up the line and his train was behind time. I imagine Wood Lane thought they were going to find a spare (T/Ops who are reserved specifically for this kind of eventuality, who can be called on to take over a train when necessary) or somebody to take over the train at LES (hence it was still showing LOU until STR). But, presumably they couldn't find anyone, so the train was terminated in WB2 until somebody could be found to take it back into central London, hopefully when it would be back on time (as in, it would leave LES when it would have left LES had it been up to LOU and then come back according to its timetable). That, of course, meant many more trains being worked into WB1 from the EPP branch :P

And, after that, it was a very nice, sunny journey home over a lovely stretch of the Central line :)