Metropolitan line future ATO

The entirety of the SSL is being given Bombardier CityFlo 650. It's moving-block ATP and ATO in one.

You couldn't just pick sections of lines. That leaves a permanent common failure point, as was seen with the Dollis Hill switching.

Currently the Met has quite far signals apart for an LU line. Moving-block will let the trains come up really close, and also means that line speed isn't an issue. That benefit has been seen on the Jubilee with some old signal sections having slow limits, and then TBTC giving thrash.

The Picc and Bakerloo could really only gain ATP with their current stock. To introduce ATO on 3-step traction systems would be absolutely ludicrous, as the jerk effect would be even worse than the current 96 setup when running at a lower target speed! Not that a t/op could do a significantly better job of that. The stepless (effectively) motoring and braking available with GTO and IGBT traction provides a far better solution, given the right ATO systems. To use a 1960s Vic signalling style ATP/ATO system just simply wouldn't be worth it.

I'd imagine an interface will be found for bog standard NR signalling, but the block lengths will lose out there.

Or the ATP/ATO could just run into Watford Junction, with conventional signals being operated by the same underlying equipment for the DC line trains.



Don't forget that the Chiltern trains already have a (life expired) ATP system and it is not too difficult to imagine that any replacement system fitted on the Chiltern routes could be made to mesh with the new Metropolitan line system, without the need of lineside signals. There is already a changeover to/from the current ATP system on the line into Marylebone.

On the shared sections of track ATO is less likely to be important than the ATP function, as trains are more spread out than in the center of London.

There's no point in not doing ATO for the rest of the line. Bearing in mind it is 100% train-bourne, taking the input from ATP!

Wasn't the uxbridge branch supposed to be the first bit converted? Or was that something to do with the 33Hz circuits

IIRC it was the latter, to allow S Stock operation. I think the east end of the District had to be done too. Can anyone confirm this?

Thanks for the confirmation.

It was always going to be one of those "whatever you do, start at the extremities, the city has always been the start point, and we've never made it much further out than that" projects.

The last attempt on the Met was with the Met SCC - where Amersham was to be added during the year 2000. The Uxbridge branch was made "SCC Ready" years ago (that is, unplug it from Rayners Lane cabin and more or less plug it into the SCC). Whitechapel was going to be added mid-2000s - probably as a political Met/District becoming "SSR" move.

Amersham and Chesham saw a fair bit of work in connection with the re-signalling and movement into one of the Interim Control Facilities just a few years ago.

So if it will be ATP and ATO in one then will it not be possible to drive the train manually with the ATP for any reason? I would have thought a separate ATP system would have been better like on the Cenral line as then the ATO box in use on the District line could take input from SelTrac when running on Piccadilly line sections and the Piccadilly line could take input from CityFlo 650 when on the Met. I would have thought an ERTMS compatible system would also have been useful for the sections where tracks are shared with the main line.

Think it just means that instead of two different pieces of equipment talking to each other (like the central) it will be one piece of kit doing both. I would highly doubt that there is no CM function.