SSR Resignalling

Is it possible that the Picc signalling will eventually include Richmond and Wimbledon? Presumably you are only talking about Acton/Ealing, and the other District branches will remain as is into the future?

I seriously doubt it. Wimbledon might come under Seltrac control one day, when Network Rail resignal the lines into Waterloo (the Wimbledon branch being on the Clapham Junction and Wimbledon interlockings), but I don't think Richmond will unless Network Rail transfer the infrastructure to TfL which seems unlikely. In terms of introducing Seltrac on NR infrastructure I think the gap in requirements between the two organisations was too great to be overcome to allow Seltrac on NR.

Was there a proposal that foresaw low-level Chiswick Park platforms on the Gunnersbury branch and the Piccadilly running both express and local services between Hammersmith and Acton Town? Or has the need to establish the Lillie Bridge replacement sidings just east of Bollo Lane/Acton Lane put that idea into abeyance? In any case District and Piccadilly services west of Barons Court (planned as part of SMA 10) have been betimes interwoven during exceptional operations; the latter’s trains serving the local (District) platforms at intermediate points. SMA 10 was always going to be complex, and fascinatingly, my copy of the 4LM ATC Status update of 21 Jan. 16 (link below) originally anticipated (with all expected overrun) a completion date of Jan 2021! It also shows the colour shading for SMA 10 as rather paler between Gunnersbury and Ravenscourt Park—absolutely of no significance, I’m sure—than at the Richmond end of the line. Up-thread DStock 7080 kindly provided insight that SMA 10 will now only include the line(s) between Barons Court and Stamford Brook and that its remainder and SMA 11 are now moribund.
content.tfl.gov.uk/fpc-160121-item11-four-lines-modernisation.pdf

Three Western branches is too many for the District Line so let's give the Piccadilly line three Western branches.

I mean, I know it's getting a bit off topic but there seems to be a logical flaw here.

Though I suppose the Picc could have 30/32tph to share out among them whereas the District still only has 16.

That was when they were considering swapping Ealing and Uxbridge right? I thought the current thinking is just to transfer the Ealing Broadway branch so the lines are mostly separated.

I suppose going from 24tph to 30tph+ will provide enough trains to cover some sort of Ealing service and with more trains they could extend the Northfields terminators all the way to Heathrow. And there's 10% (and probably more, realistically) to be gained from NTfL. So maybe it'll work. Anyway maybe I should start a separate thread on Piccadilly Line re-signalling... 

Yes but the Met is a very different railway.

That said, you have got me wondering, how many passing loops would be needed for Chesham to have a 10 minute service (alternate trains to London and Watford via the North Curve)? oh and if the second platform at Chesham was reinstated would it be long enough?

I would be very surprised if the second platform at Chesham was long enough for an S stock. It's been a while since I was there, but in my mind it's about the same length as the bay platform at Chalfont & Latimer.

The second platform at Chesham is very short with the station buildings at the end. It was used for steam locos in the past.

There is photo evidence of a second track beside the signal box but it does not appear to have had a platform. The track was removed many years ago.

It's more a case of beyond design life than anything else, though the internal wiring in the signal heads is very fragile and ad-hoc rewiring is now taking place, the external cables are lead-sheathed and prone to failing in periods of warm weather, and the wiring at Acton Town East IMR is on the wire degradtion watch-list. (Acton Town West was reqired about 20 years ago, due to wire degradation.) We have found in the past that an interlocking can be extended many years beyond the nominal 40 year design life (well illustrated at Acton Town which is now some 57 years old), but there comes a point at which it becomes a case of complete renewal by stealth rather than a planned renewal, with different cost implications.


My understanding of the way it works in NYC is that NYCTA have developed a common specification and engaged various suppliers, both Siemens and Thales, to produce equipment that meets their specification and, more critically, are interoperable with each other's components. This is similar to the BR development of Solid State Interlocking in the 1980s where BR worked with both Westinghouse and GEC with the aim that a GEC module could be interchangeable with a Westinghouse one.

Finally, in terms of the limits of CBTC, it is not intended for Barons Court to be a permanent boundary.

I saw a LT Museum picture this morning with a steam loco in the bay. I assume it was electrified as you say.

The picture showed the second track in front of the signal box with a raised area that could have become a platform.

This has certain common history elements with Seltrac itself.

Many outside observers tend to think of Seltrac as Canadian or possibly French. In origins it is not. It is German. German railways have long played with track to train communications by induction, right back to 1920s. 1960s saw development of what we today would recognise. It was initially developed for 200 km/h running and generically as LZB*** (liniebeinzugflussung).

Developed to a common standard, and in typical German industry way, by a group of companies working together (one could almost use the term cartel); the way they work is several companies bid, one gets to be the lead, but not only do all the bidders get a slice of the contract, the leader contractor may actually be leading a rival's product - and all items are required to be interoperable and interchangeable+++. I don't know the ins and outs of DB main line LZB other than the main contractors were Siemens and Lorenz, and, so far as I understand it, the original hardware engineering was Siemens combined with Lorenz's signalling expertise.

Since 1960s the system has evolved with numerous bespoke set-ups and a range of standard products diverging in various ways from the original idea. The version LU has was developed along the Lorenz (who had other names on the way such as SEL and Alcatel) product line. The 'sel' of 'Seltrac' is a throw back to SEL, Standard Elektrik Lorenz (or something like that).

Anyway the point of my rambling is the system we have now did originally come from a standard spec for interoperability and interchangeability. If only GB had gone that way. Had we done so, things like the ability to integrate Chiltern trains ATP (which is an Alcatel product that got split off from a branch of the same product line many years back) into LU's Seltrac hence dispense with tripcocks that way might have been a lot simpler. And that's just one example.


*** euro-trainspotters tend to get worked up over this term; I am using it here in its generic sense, not the specific version fitted to different generations of different trains on different lines


+++ the classic example of this that GB trainspotters love to quote is main line D800 (Warship) were built by Swindon and NBL, and originally intended different engines and transmissions makes would be fully interchangeable, like the orginal DB V200 they were based on; for various reasons (in simple terms typical British dumbing down) it did not happen; anyway, it is not usually realised by many authors, and it comes through in writings, that this is normal German engineering practice; while it was more or less unique for BR diesel traction, although not carried through, writers do tend to reproduce wording that suggests this was something unique to V200 hence D800. In reality it applied, before the days of EU deregulation, to almost all large German industry contracts.

Before this goes further off-topic (very interesting though it is) wheel wear doesn't impede functionality, but increases the risk of nuisance trips as the tripcock arm is below the correct height.
This gives rise to the risk of tripping on tripcock testers (which check for, amongst other things, that the arm isn't set to low) and other objects/debris on the track.

In the same way that trainstops have to be adjusted for rail wear (to keep the trainstop head within the 3" ±1/8" above the running rail) the trip arms need similar adjustment so they don't go lower than they should when the wheels wear.

As an aside, I get the impression German metros wouldn't go near Seltrac these days as it's rather old tech now.

This is a bit of a digression but it fits after a recent couple of posts - the Chilterns line ATP system was, at time of install, Alactel SelCab _ you see the 'sel' name and Alcatel again _ which, as this overview :

www.traintesting.com/chiltern_ATP.htm

says did not get fitted on the LT section.

I was looking for it, somewhere I have seen a compatibility relationship of different Seltrac release versions with different Selcab release versions; I can't find it, it might even have been something I read back when I briefly worked for Alcatel, but, fairly sure ISTR if the existing main line Chiltern 165s had had one higher version of Selcab, then it had compatability with the Seltrac version LU has. But. That is NOT to say in any way it would be plug-and-play, there would still be signficant integration work to make it function.

As as aside, BR was in it's dual sourcing mode phase when it procured ATP; the GW route from Paddington kit was supplied by ACEC

www.traintesting.com/GWML%20ATP.htm

BR dual sourced and bought two different products. DB made the suppliers work together and bought one. Kreide und Käse. Or is that craie et fromage ?

End of my digression.