"Jonathan Morton" wrote in
message ...

As a matter of interest, are dual-voltage trains disproportionately
expensive? It's something we may see more of, given some of the
assumptions in the RUS. In particular, the "Reading-Basingstoke-Salisbury
at 25kV" idea is rather surprising, since it would need elements of dual
electrification (Basingstoke to Worting Junction) and dual-voltage trains.


Not really because by the nature of modern Variable Voltage Variable
Frequency (VVVF) motor control there is a DC stage in the conversion process
from 25 kV, and this is where the DC power from the third rail would come
in.

All current/new EMUs are either dual voltage capable as deliverered, or
easily convertible with a minimum of extra equipment, dependent on their
initial sphere of operations. Usually a case of adding a pan, and
transformer/converter to a DC unit such as a 450 - the pan controls are
already in the cab panels - or adding shoe gear and wiring to the equivalent
AC unit such as a 350. Is there a modern unit that doesn't already have a
pan well in one car?

In your example, if changeover on the move is specified the OHLE wouldn't
need to start until Battledown flyover or beyond. There wouldn't necessarily
need to be dual voltage supplies all the way from Basingstoke, although if
AC also arrives via Reading it might be an option?

I wasn't too surprised at this route - it does seem an obvious early
candidate (and they explain why) - I was quite surprised to see Cardiff -
Portsmouth as an eventual scheme, noting all the scepticism in the past
about the SW in general, eg Exeter via Westbury was generally predicted to
be a non - starter...

Paul S

"Paul Scott" wrote in message
...

All current/new EMUs are either dual voltage capable as deliverered, or
easily convertible with a minimum of extra equipment, dependent on their
initial sphere of operations. Usually a case of adding a pan, and
transformer/converter to a DC unit such as a 450 - the pan controls are
already in the cab panels - or adding shoe gear and wiring to the
equivalent
AC unit such as a 350.

Just to clarify or expand on that, the LM 350/1 only needed 'shoes'
refitting for their current WLL DC use, the 350/2s would need complete shoe
gear, ie pick up shoe, shoe beam and shoe arm (and probably some bogie
wiring).

Paul