ATO on Thameslink

Interesting that only one button needs to be pressed in order to start ATO - it’s always two on LU.

Probably not unique once Crossrail is fully up and running. I agree Thameslink's reach is far greater than Crossrail but there are still inter-dependencies for CR with other services and at least three infrastructure providers (Crossrail Infrastructure Ltd, Heathrow's tunnels, Network Rail). Thameslink just has to cope with Network Rail's infrastructure. Crossrail will have three signalling systems to cope with whereas Thameslink has two.

If I have been paying attention to Roger Ford's writings then Thameslink will be covered by Traffic Management Systems (TMS) that "pick up" the pathing of trains a long way out from the core and the ATO transition points. This at least gives signallers some chance to address any late running trains or to cope with out of sequence running. One can only hope that a lot of work is being done off the back of real life disruptions to fine tune or test these traffic management systems and the interraction with ATO. I understand Thameslink has been clobbered today with a power failure at East Croydon, points failures and train failures (Southern not TL trains) on the network. The impact of this would form an interesting test scenario for TMS - assuming TMS is not yet in full use by the signallers on the various routes that Thameslink uses.

Yes but I was referring to the "unique spectacle" aspect of the post not the train length.

Next correction?

Due to the use of very tight Victorian infrastructure those 12 cars are only 20m long.

Crossrail stock by contrast is 23m at least - the same as a Mk3 coach.

10 x 23m (e.g. Two 442 units) is near enough the same length as 12 x 20m.

in other words despite having fewer individual vehicles, a full length (as in the maximum that the stations have been designed to eventually be able to cope with) Crossrail train will be longer than a FLU 700, despite having only having 11 coaches as opposed to 12.

Thank you.

I thought they were a bit longer than 23m, but apparently not! This is a technical diagram:

www.whatdotheyknow.com/request/349041/response/857315/attach/3/Q234 BMB R1 XMO CR001 50011 Rev 3.0.pdf

DMs 23.6m, middle cars 22.5m. Platform tunnels are being constructed to "over 250m" so a full 11 car train of this stock (should that be pursued as an option) will be 249.7m.

Its a really good thing they went for three sets of doors per car - having only two per car on most metro stock must cause dwell time nightmares! To think that the 4DD was canned because having only 5 or 7 single doors per carriage was then thought a liability!

I can’t see any system being allowed where passing a signal at red is allowed in normal operation. Red surely has to mean stop, regardless of the mode of operation.

One option could be that the fixed light signals don’t apply in ATO? I have no idea if that is the case, just puttingit out the as a hypothesis to a system.

Not on Thameslink it doesn't. There is a secondary system in play in the Thameslink Core know as PoSA (IIRC it's Permission on Sight Authorty) which overrides the normal signalling systems. Means trains can keep moving even when there's a signal failure. Just has to be turned on and then does it's own thing automatically. Been used in service for many years now without incident.

It seems odd that 377s are allowed and 375s are not, as they are essentially the same, at least for gauging purposes - indeed many 377s were originally classified as 375s.