SSR resignalling

[D7666]

With some of Chiltern’s DMUs reaching end-of-life in the foreseeable future, will whatever new replacement rolling stock that Chiltern gets in the future have to have multiple signalling systems, including CBTC, or will they just remain tripcock-based?

Any future Chiltern main line stock will almost certainly have an ETCS solution for Met line operation; ETCS and CBTC are not dissimilar when it comes to underlying signalling principles - it is the track to train communications path and the bespoke software applications that are different. A very simple view is all that is needed is for new Chiltern stock be ETCS fitted but with additional CBTC antennae and the conversion done by train borne processors, or, for Met line trackside CBTC kit to transmit ETCS messages, or for the central 4LM CBTC processors to communicate with the central NR ETCS processors. This type of integration of dual ETCS / CBTC equipped trains is already in place on 345s that have (Siemens) CBTC for the Eliz line core and ETCS for Heathrow Airport - it is not unknown territory. Hitachi/Thales CBTC is simply another variation, not a blocking point. IIMU a longer term aspiration, at least a concept not plan, for LU Ealing / Richmond / Wimbledon is some form of integration with ETCS when NR do eventually get around to it.

 

[bramling]

With some of Chiltern’s DMUs reaching end-of-life in the foreseeable future, will whatever new replacement rolling stock that Chiltern gets in the future have to have multiple signalling systems, including CBTC, or will they just remain tripcock-based?

There’s probably no real need for CBTC. What might become an issue is if it becomes impracticable to fit tripcocks to Chiltern stock, or if LU wish to take the opportunity to ditch the trackside trainstops. Presumably the CBTC system could achieve the same level of protection with TPWS fitted, though there’s the question of who pays.

However, I agree with the view that it will probably be left in the “too difficult” box until such time as it needs to be tackled, and probably end up with an ETCS-based solution, probably at considerable cost getting all the various stakeholders to talk to each other.

 

[zwk500]

and probably end up with an ETCS-based solution, probably at considerable cost getting all the various stakeholders to talk to each other.

Not impossible that it could be an ETCS Level 1 applied to the signals already overlaid on the CBTC interlocking. It's LU infrastructure so NR's preference for L2 wouldn't be an issue, and the Chiltern units wouldn't need any kit they're not already getting. And it potentially makes the transitions to NR easier as well because it'd just be L1 to NTC/L2 (as appropriate).

1 issue with this would be if the Eurobalises and Euroloops would be non-interfering with the CBTC beacons and v.v., and whether LU would want to get certified for installing and maintaining ETCS which they otherwise wouldn't be using.

 

[penfold22]

Any replacement trains in the future will still be required to be tripcock fitted. The introduction of CBTC north of Harrow does not affect Chiltern trains in terms of general operation - the drivers run to colour light signals and have to have operational tripcock equipment. The current and any subsequent fleets are not and will not be CBTC fitted.

It has taken this long to get CBTC and there are no plans in the long foreseeable future for any additional systems to work alongside it (eg ETCS etc.)

 

[A60stock]

Is there some sort of TSR or something just outside Wembley Park southbound? All fast trains I have been on have either stopped in the platform or performed a sharp break just after passing through

 

[penfold22]

Unfortunately we have several TSRs across the line, but nothing in that area that would cause that. Given you mention running on the southbound fast I would presume they have been trains in the morning peak? The number of trains operated southbound especially between 0730-0900 can still cause some congestion even with CBTC in charge. Occasionally, the system does get a little too enthusiastic and in its efforts to recover time and get trains as close together as designed, it can catch itself out and as a result certain trains may be slowed at the last minute. Nothing unsafe in what it is doing - in fact the reverse, in that it is being sometimes over-cautious.

 

[A60stock]

Yes, morning peak.

That makes sense, I thought maybe the driver applied the break as a precaution or something!