Tuesday 25 June 2013

Automatic For The People

While en tour over the weekend visiting Paris – as one does at this time of the year – I used the city’s Metro network to get around the sights. And, following all the heat generated by London’s occasional Mayor Alexander Boris de Pfeffel Johnson over the idea of automatic operation for London’s Underground, I also checked out how this is accomplished in Paris.
Odd French technology (not an automatic route this)

And the answer is, it’s done in a way that will be impossible to replicate over almost all of the London system. Paris now has two Metro lines operating on automatic – Line 1 was the example touted to Londoners of how to convert an existing route, with Line 14, the newest on the system, having followed more recently. Both these lines are simple end to end operations.

Moreover, they have little or no exposure above ground: Line 1 comes into the open briefly at Bastille, and when it crosses the Seine, and that is that. There is nothing on the scale of the surface sections of Tube and Sub-surface Lines (SSLs) in London. And both these lines have platform doors at all stations (the 14 was built with them). This, though, does not hamper ventilation.

That is because Line 1 runs in double track tunnel (rather like the SSLs in London), and so there is none of the constraint that tube tunnels would impose. Platform doors on older Tube lines would make ventilation of the stations more difficult. And then there is the particularly French running gear, which most certainly does not exist anywhere on the London system.

Some lines on the Paris system have been adapted to use rubber-tyred trains: these still have conventional tracks, but only for guidance. This is supposed to produce a quieter and smoother ride, but modern suspension systems for conventional rail vehicles do just as well. The automatic lines use this system. So is Bozza looking to bring that to the UK? He doesn’t know. He’s shooting from the hip.

So how do the automatic trains perform? The acceleration and braking is often unsubtle in the way that Automatic Train Operation (ATO) was on the Central Line when first used over a decade ago. There are occasional “pathing stops” as trains are ordered to wait at stations to even out the gaps between them. And the ones on Line 1 suffer from braking snatch, often juddering to a stop.

To be fair, ATO on the Tube does better than that, so the version used in Paris probably needs a couple of software revisions to improve things. And the punters seem to like sitting up front, even though there is nothing to see for most of the journey. But London doesn’t have simple end to end lines in double track tunnel with almost all the route underground or easily fenced off.

So the comparison with Paris is largely meaningless. No change there, then.

1 comment:

  1. The question, then, is where might one find a driverless ATO line that's mostly above ground, features several single-bore tunnels, has no PEDs, and a multiplicity of junctions and routes?