Michael Bell wrote:
In article , Richard
J. wrote:
Michael Bell wrote:
It has always seemed to me that the 750 volt 3rd rail is a bad
idea. snip So I have been thinking of the possibilities
of shielding the 3rd rail. snip

Other people have designed such systems too. There is one already in
operation in London - the DLR.

To complete this would obviously be a 10 or 20 year project,
(even longer to replace some of the longer-lived stock with higher
voltage stock) but some of the benefits, such as no icing in winter,
would come immediately.

Your design includes a plastic cover over the top of the rail.
Doesn't this prevent existing stock from using rails fitted with
your plastic covers? I don't understand how you intend to operate
during the 10-20 year conversion period.


Obviously the fleet has to be modified first. That's the smallest part
of the job!

Ah, so the fleet is modified in such a way that it can use both the old and
the new design of rail. Not exactly a trivial task.

Also, have you done any sort of cost-benefit analysis for this
project?

No, I have done no cost-benefit analyis.

So you have proposed an expensive project for safety reasons which HSE don't
consider mandatory, with no analysis of whether it's worth spending the
money. I think you need to justify it better than that.

But if DLR (which I should have thought of) have done it, and foreign
systems have done it, then they must have made some sort of calculation.

DLR did it AFAIK because by then it was mandatory for new systems. The fact
that HSE did not mandate changing existing networks suggests that this would
not produce a reasonable cost-benefit.
--
Richard J.
(to e-mail me, swap uk and yon in address)