The runaway train went down the hill... and I expect many people blew out a huge sigh of relief when she stopped. I know the whole thing made me freak out and I'm at home today.
It's a bit unclear how that happened and the story is still coming out but I have a few theories.
passengeraction and I have been kicking around ideas throughout the day and have built a fairly solid case. Of course, without actually knowing anything we are just supposing so I expect we'll have to wait for the official HMRI report like everybody else.
HMRI, for those who don't know are Her Majesty's Railway Inspectorate*. They are the people who supervise the country's railways and make recommendations for running. There's also the Rail Accident Investigation Branch(RAIB) which...er...does exactly what it says on the tin. They'll be taking a very close look at what happened here and making their own recommendations. I would heartily recommend going through some of their published reports (they are online) because they make for great reading. Everything is noted and commented on and I do mean EVERYTHING. One of my favourite reports had a paragraph buried in the middle which noted that Driver A walked past Driver B and that the two drivers "acknowledged" one another. I've probably spent hours pondering exactly how that acknowledgement took place in real life. :-D
As to what happened. Who knows. We have to wait. What is known at this stage is that it wasn't a passenger train which broke away. Trains which are in passenger service have a ton of safety gear on them which renders it impossible for such a thing to happen. If one half of a train breaks away or (as in this case) a defective train breaks away from the train towing it then brakes go on all over the place. During a tow (a pullout) there are also rather sensible precautions whereby there's always a driver on each train so that things can be stopped if there's a need. In addition to all of that there is gear on the track which knocks on the emergency brakes if a train passes a signal at danger. I'm not going to go in great detail about these systems as there are several different types of train in use on the underground and each one has different ways of implementing the safety features. But what is certain is that the safety features are there on all passenger trains and the default state of a train which could be dangerous is stationary.
Today, the train which broke away was an engineering train. You've probably seen one about the tube at some point. They are usually little yellow things and they pull wagons full of ballast or equipment. It would seem that there was work overnight somewhere and in the early morning the train was making it's way back to it's depot. It then broke down and was towed by another train and then broke away. Now I don't know much about engineering trains but I do know they are generally pretty basic. So it could well be that some of the safety systems which are in operation on passenger trains are not required to be installed on little locos. It could also be the case that equipment failed in an unexpected way. If eiter of these are the case then I strongly suspect that better equipment will be installed in short order. The alternative is likely to be every driver refusing to work if engineering trains are permitted on the track.
I'm not a particularly rabid unionist but the thought that an unattended train with no viable brakes could come hurtling down the tunnel towards me is horrifying. The initial reports suggest that the nearest the runaway came to any other train was about half a mile. There's a rather hysterical RMT spokesperson saying there was almost a collision but I'm discounting that because, well, because it's RMT. But still, half a mile is too damn close as far as I'm concerned. I would very much like it if I and my passengers did not get unexpectedly smooshed as we went about our day! I suspect we will be experiencing the shockwaves about this for quite a while.
*It's now been renamed but within rail companies we still refer to HMRI.