Upgrades on the Chesham branch

I A G R E E !

If you can hear clickety clack then it is the old jointed rail.

no long welded sections there just 30ft rail

Long Welded Rails have been in use on the Underground for nearly seventy years ( the first rail welding plant was installed at Lillie Bridge in 1937) and makes up the vast majority of track on the Underground.
'Reconstructing London's Underground' by HG Follenfant says the following:

Flash Butt Welded rail was first installed in the United Kingdom on London Transport railways, where it is standard for every location, except on curves of 15 chains radius or less, through points and crossings, at places where there is alternate covered and open conditions, and in cuttings where clearances are such that the de-stressing drill cannot be carried out with day-time observation. The rails are welded into nominal 300 ft lengths, tailor made to suit insulated joint positions and jointed into ½ mile lengths by machine fitted fishplates and fitted fishbolts so that there is a running surface on the rail free of gaps except at the insulated joints between signalling track circuits, where the gaps are filled with insulation material. The ½ mile lengths are separated by stress adjustment switches.

Interestingly it also says

Up to 1960 there was a greater mileage of long welded rails on London Transport than in the whole of the remainder of the United Kingdom, and all flash butt welded rails installed experimentally on British Railways prior to 1947 were welded by London Transport at Lillie Bridge.

What this all means is that is that when you go and look at a stretch of track on the Underground, while it may at first glance look like jointed track you won't have to go far to find a place where the rails have been welded together.

Long Welded Rails.

Is it practicable to lay LWRs in single Line tunnels or have any that are there been welded on the site after laying ?

Yes thats what hey would have to do, but close it for a month of two and get the whole lot done at once

Well, how long is the Chesham Branch???

Solution: Take the answer off of 41.5 miles....

When I originally posed the question, I suspected that Rickmansworth to Croxley might be the missing part of the equation. I'm probably looking at the same map as you which suggests Moor Park to Ricky at 2.09 miles and Moor Park to Croxley at 1.83 miles. QED and by jove, I think we may have found the missing bit of track???

To go back to the original question, is it a No?

btw I think this is the first time I've started a new topic. Fascinating how things meander around.