End of the Chesham shuttle

None of the suggested options will be taken up. The crossover and siding at Northwood and the bay platform at Chalfont will be removed as part of enabling works for the resignalling.

When I first read Tom's suggestion I thought the same thing as MM! My immediate reaction was that does nobody remember what has been lost in the past? I know I keep wittering on about North Ealing crossover, but when it was slated for removal it was widely said in my earshot by those whom I respect on the Underground that this meant losing a vital facility.

I am sure most of the older members can think of examples on lines where crossovers have been removed, and which has been subsequently proven to be short-sighted. I realise that costs are involved but sometimes one has to learn from the past and swallow the 'economic pill'.

Thats a really good idea!


... is something that will not be heard about either option.

It just seems really really short sighted, as presumably there will be no passive provision or money for projects to be done in the future. How did those decisions come about, out of interest?

Early this morning there was a points failure at Chalfont & Latimer which resulted in the first train from Chesham, an 8 car train to Watford, being run into the short bay platform at Chalfont. The few passengers were walked through the train to the front carriages, where staff opened one set of doors to allow them to alight.

This got me thinking about the new timetable and the S Stock.

In the event of a failure on the north Met main (either the junction at Chalfont or elsewhere), why not isolate the branch and run an S8 as a shuttle, using the fancy new selective door opening to only open doors in the front half of the train at Chalfont?

The SDO on the S8 operates only on the front and rear four doors.

Thank you for making me aware!

I was not suggesting the selective door opening was a new procedure, just that the selective door opening on the 'new' S stock could be used to select different sets of doors at different stations.

Can the operator of an S Stock choose to open only the front two sets of doors? That would be fancy!

I thought the bay at Chalfont was planned to be taken out of use. Where would the train go then, if the points had failed? Back to Chesham?

Isn't the M door designed in such a way that it incorporates steps down to the track for official detrainment?

I believe that only the 73TS and 96TS have proper detrainment stairs; OTOH if you mean just bits, not a full staircase, then IDK.

The S stock and 92ts has similar - but I don't know about the 09s.

Leave it out. Leaves will always be a problem in that neck of the woods. The only solution is to chop down the trees in the neighborhood of the track - but Miss Tree Chopper might well have something to say about it

I think knap poses an interesting question though...

If, at the moment, services stop running direct to chesham due to leaves etc. what's going to happen when there's no shuttle service?

The reason they don't run it is because the points at Chalfont are unreliable in the leaf season, running a ricky shuttle isn't going to help the matter unfortunately.

There is absolutely nothing wrong with the points at Chalfont.

Brief Leaf-Fall Problems Lesson:

Leaves, especially the residue they get compacted into, causes us (and some other rail networks) problems with rail adhesion, and a little more importantly, it can interfere with the proper detection of trains by the signalling system.
To combat both problems (which are most common at the northern end of the Met Line) the signalling is altered for the period of "leaf fall."

Larger overlaps are introduced (to combat any risk of a train sliding past a signal) and the signalling is changed to ensure that any "non-detection" that is sensed by the equipment, causes signals to the rear to be kept at danger.

End of lesson for now, although I can get a little deeper if requested.


Now, with regard to the sometimes frequent problems that encounter the Chalfont and Chesham areas, the shuttle gets "locked-in." This means it can effectively run up and down, and if any signalling problems occur, the route is already fully secured. The same is true if problems occur on the "main." It means that ultimately the service is less likely to be suspended.

The drawback for this "damage limitation" is that the evening through Chesham services are diverted to Amersham - with a connection made at Chalfont for the shuttle. Inconvenient to some I agree, but it would be slightly more inconvenient if the branch was suspended.

Moving on to this time next year...

Who knows to be honest. The S-stock has it's own sanding equipment, and may be better equipped to deal with poor rail adhesion.

This won't cure the signalling side of things though, so I guess it will be a "wait and see." I am sure those upstairs are using the current situation as a timely prompt to start thinking about next year.

What I do know is:
NO 4-car A-stocks will be kept to run an ad-hoc shuttle **
NO S-stocks will be locked-in on the branch to provide a shuttle.



** Well maybe just 1, but at present it won't be for passenger service. Let's just say cameras at the ready this time next year