Probably one of the most common reasons passengers hear of for delays on London Underground are signal failures. They come in various forms, as signalling equipment is pretty complex stuff involving the physical signals, electrical circuits, cabling and, of course, the equipment in the signalling centres themselves.
So when something goes wrong it can take time to trace the root of the problem and then resolve it. The pages in this site on Signalling will give you some insight into these complexities, so I'm not going to go into the technical stuff here.
This piece actually comprises two separate events, both within three days of each other but which demonstrate firstly how disruptive they can be and also how they just occur without warning.
The last few weekends on the District Line have been subject to a Special Timetable because of works being done to a bridge in the West Ham area and, although undoubtedly inconvenient, have seen a pretty reliable and consistent service.
Last weekend was the first for a while when we were working to our normal timetable. I was on a 'spare' duty, which essentially means providing cover for uncovered duties, either in whole or in part. When I booked on at about 0550 I was given a whole 'turn'. My train was due to come out of Ealing Common Depot at about 0625 and my 'first half' was booked to go to High Street Kensington, Richmond, Upminster and then back to Earls Court where I would be relieved for my meal break at about 1000.
I walked over to the depot with a couple of other drivers, and as we arrived we were greeted by the Shunter looking for one of my colleagues with the message that his train was cancelled due to a signal failure at Hammersmith, but he was to stay with the train and await further instructions. There inevitably followed a bit of banter along the lines of 'some people have all the luck' and, with that, we went to our various trains to prepare them for service.
I'd only been on my train for less than five minutes when the shunter called me on the radio. He advised me that I too was cancelled and, as with my colleague, to stay with the train and await further instructions. So I prepared the train, went into the depot to get myself a coffee and returned to the train. I settled down with my book (a good way to pass the time) and waited as instructed.
In situations like this you have no idea what's going on as the train radio automatically switches to the Depot Channel as it enters the depot, so you can't hear any conversation from the Line Controller.
Eventually at about 0745 the Shunter calls up and tells me that I'm to put the train up as a Barking service and to draw down to the outlet signal. This is all duly done and I leave the depot at 0750. An uneventful trip then starts, but this all changes as I come into the Hammersmith platform. I can see one of our Duty Managers standing at the end of the platform holding a red light, which overrides the green signal being displayed.
It's now about 0802. He tells me that I'm going to be used to provide protection for the Emergency Response Unit (ERU) team that are working on the defect, which has been diagnosed as a broken insulated block joint (these are used to separate the various signalling sections from each other) and they are going to replace it – a job that shouldn't take more than about ten minutes or so. He takes my keys to ensure the train can't be moved – a standard procedure in these circumstances. I advise my passengers of this delay, but add the rider that as we could be held for some time they'd be well advised to take the Piccadilly Line to Earls Court and then return to the District Line there.
I told the DMT that I was going to close the train up and switch the lights off so that we wouldn't need to re-announce the situation. I think he thought I was being a little pessimistic, but I walked down the train and closed the doors up.
This turned out to have been a wise move as it turned out. Back on the front of the train I'm watching the affected signal that is now going from red to green, back to red and then red and green together – just like Christmas!
Then the next thing that occurs is the sight of the ERU team coming quickly back to the platform. They've replaced the block joint, but have discovered there's also a broken rail that is exacerbating the problem, and this needs to be welded up to fix. They hurry of to their vehicle to fetch the appropriate equipment.
By this time I can hear the Controller on the radio reversing trains so that nothing else heads down to either Richmond or Ealing Broadway Westbound and instructing trains now queuing behind me to move up, applying various procedures to achieve this. The DMT now gets me to move my train as far up to the Station Starter as possible so that the train behind me (now empty, having detrained at Ravenscourt Park) can move right up behind me.
The ERU team are by now back on site and eventually indicate that all's fixed. It's now 0850 – I've been at Hammersmith now for over forty-five minutes. My train is, of course, well past the end of the platform and as there's another train right behind it's more straight forward to leave Hammersmith empty and go back into service at Barons Court. This is all done, and I'm running normally towards Earls Court, mentally calculating whether or not I can make Barking and back to Earls Court within my permitted driving time. I've got no chance of getting through to the Controller – the radio's one constant stream of radio calls from him advising drivers of where to go and what to do. I've worked out that I can make Tower Hill and back (and possibly Whitechapel, depending on progress through the City), so I decide to carry on until I get a bit further east and when the radio quietens down.
It's just about 0900 as I pull in to Platform 1 at Earls Court. The platform describer is showing the train as an Upminster service, although I'm not really surprised at this. As I draw up another driver walks up, tells me the train's being reformed and to report to the DMT.
So I go over to his office and am told just to start to my meal break and to pick up my next train as booked – this isn't due until 1049, so I get the benefit of almost a two-hour break! There are already others in the canteen in much the same situation, although some were due to have had their break at either Upminster or Barking where they were, of course, due to pick up their next trains. So to make everything worse, we've also got drivers in the wrong place!
By the time I pick up my second train everything's pretty well back to normal, but only just. So a failure at just after 0500 has taken almost five hours to resolve and for the service to be recovered.
Only two days later I book on for a late turn at Acton at about 1520. I'm due to pick up my train at Acton Town Eastbound at about 1530, but the DMT on duty warns me that it might be late as there's yet another signal failure at Hammersmith – I'm hit with a feeling of deja vue!
In the event my train arrives only about ten minutes late. I'm due to go to Barking, Wimbledon, Tower Hill and back to Earls Court for my break. All goes reasonably well. The signalman at Barking reverses me in the bay platform (rather than via the sidings, which what the train's booked to do) which saves some time, but I arrive back at Wimbledon about fifteen minutes late at about 1805 – I should have departed at 1802. There are already trains there, but I have a word with the driver and discover he's due out after me and he agrees that I can go first.
So I duly 'plunge' to let the signalman know I'm ready to depart. Nothing happens – all the other platforms are occupied, and all the signals are red, so it's not that he's letting someone else go first or waiting for a train to come in. I plunge again – same result. I plunge for a third time – it's now 1815 and I'm supposed t go to Tower Hill and back before I get relieved. The probability of a short meal relief is looming large!
I get on the signal phone and am told that 'there seems to be some sort of obstruction on the line – we can't clear any routes!' Great! I announce this to my passengers and give them the gloomy news that I've got no idea how long we're likely to be there. I'm reluctant to leave my train to use the 'Autophone' to phone the Controller (the radio's no good at Wimbledon – it's well known as a 'black hole') as this is sited at the far end of the platform in case the situation resolves and the signal clears, so I call the Controller from my mobile phone (often a driver's best friend these days) to see if he knows what's going on. He can't really add too much – remember Wimbledon's a Railtrack station and subject to their signalling, so he's relying on the Wimbledon signalling staff keeping him advised.
Eventually the problem is still resolved (I still don't know the exact cause) and I depart at 1840 – the train's due to be leaving Tower Hill coming back in ten minutes! As I work up to Earls Court I get further delayed by trains that have been reversed at Putney Bridge and Parsons Green. The platform describers are clearly confused as I'm being described as an Edgware Road service (not possible with a D Stock – they won't fit!), Tower Hill (OK – that's where it's due to go) and finally as I arrive at Earls Court as an Upminster train! I wonder if the train's being reformed but there's no sign of a relief.
I get out and use the phone. I tell the Controller of the description and that I'm booked for Tower Hill. He says 'booked destination then driver'. I point out that I should be back at Earls Court in less than ten minutes, and wouldn't it be an idea to send me to High Street Kensington and then at least the train'll be more or less on time. 'Good idea driver – I'll tell the signalman'
I get to High Street, change ends, and leave reasonably quickly, arriving back at Earls Court at about 1925 – only about ten minutes later than booked.
So again, there was a significant shutdown, but this time in the evening 'peak' so a huge number of passengers were delayed, diverted and generally inconvenienced by a situation no one could predict.
In fact on this evening we'd had a failure at Hammersmith and Wimbledon and the Metropolitan Line had suffered two similar failures, which also impacts on our Edgware Road service.
So again we had a disrupted service that took time to recover, and resulted in trains being diverted – either because they were unable to make their 'booked' destination or reversed short to try to recover the service.