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Old February 9th 19, 12:40 PM posted to uk.railway,uk.transport.london
Anna Noyd-Dryver Anna Noyd-Dryver is offline
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Default DfT favours battery trams

Clank wrote:
Anna Noyd-Dryver Wrote in message:
Clank wrote: On the other hand... What's
wrong with trolley poles? They seem pretty reliable even in inclement
weather*. On a tram, where the poles wouldn't even have to deal with
the vehicle moving all over the road to overtake etc., I don't see any
reason why they should be particularly problematic. More prone to
dewirement, particularly as speed increases. Junction'pointwork' more
complicated and prone to failure. More maintenancerequired too, I think.
Need changing over at every terminus. Anna Noyd-Dryver


With all due respect - and I use that in its extremely unusual totally
sincere sense - are all those true, or are they just "received wisdom"
used to back-justify the UK's resistance to trolleys (and indeed trams)?


My post was based on my knowledge and experience of UK heritage tramway
operations, my knowledge of UK heritage tramway maintenance, and of OLE
equipment fitted; and finally the fact that non-heritage tramways using
trolleypoles rather than pantographs are a tiny minority if indeed any
exist at all.

The junction pointwork here is generally lightweight and simple, and even
if it wasn't how much trouble would it be; an awful lot (crossovers etc.)
can be done entirely passively, so given that a system like Croydon
Tramlink would require all of about 3* sets of points how much overhead
(no pun intended) do they really add?

* Approximately, and I've not looked in detail, but pretty sure the
central loop, and all the various sets of track points for the single
line sections on the Wimbledon branch could be handled by passive trolley
OHL with no points required - so the only places you need actual points
in the OHL are Sandilands, Arena & Church Street.


Even in the trailing direction, a frog casting in the OLE presents a
disruption to smooth passage of the trolley head, and extra complication to
the layout of wiring and supporting wires, compared to having two plain
wires which don’t even have to touch.

Taking Croydon specifically, with a little imagination you could get away
without a facing frog in the OLE leaving any of the termini or the single
line sections, however you’d need them for entering the three double-track
termini, at each end of the depot (and vastly increased complication within
the depot), at Church Street, Sandilands, Arena and each end of East
Croydon.

Plus, of course, you lose flexibility for any unusual working, wrong line
moves etc, without added operational complication.


Anna Noyd-Dryver