Train protection on NR shared lines

North of Queen's Park both are fitted - IIRC they are electric trainstops rather than pneumatic.

Quite right!
;D ;D ;D ;D

Indeed. The premier railway in the world had a terminus named after a poisonous metallic compound, and was kept running to supply a rather insignifcant project in Manhatten.

Any guesses?

EDIT: Why is it unusual to have TPWS at every signal on the Wimbledon branch - I'd have thought that the traffic density/cramped headway curve made this desirable? Especially (if failing memory serves correctly) every signal is sighted sited as a compromise between the differing braking characteristics of the stock used on the line? I may very well be wrong here.

It's certainly not unusual nowadays - pretty much every single on the Wessex region is fitted with TPWS.

This may be a germane illustration of a modern interface between LU and NR.

tinyurl.com/5gpyot

The source document for this is the September 1990 abolition of East Putney, Wimbledon Park and Wimbledon 'A'. Reversible road working was also instituted between East Putney and Point Pleasant.

Note how the trainstops are absent on the Up/Down Putney leading to the reversible Putney line. The distances in yards between successive signals seems slightly closer together to me than I would expect (see comment above about siting), though without digging out the gradient profile and doing some calculations I couldn't be too sure.

Unfortunately this predates the installation of TPWS, but as this would have been a retrofitting exercise I wouldn't have expected the signals to be moved around too much (as the triggering grids are more portable). Also of interest is the FRL featured in the quiz at Wimbledon Park a few days ago being shewn on the wrong side of the track on the plan (not uncommon these days with drawings) .

Signalling Plans are not well suited to this medium - if anyone is really interested please PM me, and I'll see what I can do; bandwidth permitting.

It is also worth noting that this document complys with the guidelines for 'sensitive stuff' on this site.

The trainstops fitted between QP & HW are actually hydraulic operated, the dirty silver box next to each one is a pump unit to drive the trainstop down. The return to the raised position is by a very large spring under the the thin metal passing under the trip arm. The hydraulic oil is stored in a reservoir in the base of the pump unit, the signalling will power the pump when the section is clear and drive the ram below the spring to push the triparm down. The proving of the arm down will then allow the signal to clear, thus the aspect will change red to proceed and has no dual aspect as per LUL signalling. From this can come the problem which is that the triparm has driven down correctly but the down proving has failed and therefore the signal will remain at red. This is a right side fault in that the section ahead is clear but the signal remains at red and the correct aspect sequence is seen on approach. One problem that was found during the 1980's when the first one was installed as a replacement for the 1930's all electric version. This was that the large spring forms quite a resistance to the pump unit and continues to try and force the trip arm up. This has the action of forcing oil back to the pump unit valve, which is all that retains the triparm down. Any contamination of the hydraulic oil can prevent the valve from sealing fully and oil will trickle back to the reservoir and allow the triparm to slowly raise. This will break the down proving contacts and the pump will drive the triparm down again. This can lead to a ripple effect on signals in rear and many a good t/op has been caught by a trainstop raising and lowering rapidly at what was a clear signal. The valve is released when the signalling require the trainstop raised and the oil will flood back to the reservoir by action of the return spring.

I think I may have gone on too long.