Re: Near miss at Victoria (London)

["Aus Visitor" <if-u-know@cwcom.net>]

Chris Downs wrote in message ...
>SNIP SNIP
>
>A question to those in the know:  In many thousands of km travel on
Brizzie's
>sparks I have never seen serious arcing between the pantograph and overhead
as
>I've seen in Sydney on occasions.  But my old man told me such arcing was
>common on some trips he made under 25kV in the UK (loco hauled trains in
all
>cases I think).  Why is this so, overhead quality/age, higher current for
>electric locos or?

Arcing is less in AC systems as the arc is self extinguising and the current
per pantograph is less when the volts are 25 kV.  Multiple Electric units
often have two pans so current draw is shared, so even less current per pan.

An AC Loco, on the UK system travelling at 125 MPH, is drawing all current
through a single pan so losts to spark.  Biggest impact is frost & ice in
the catenary wire.  I remember some IC225 test runs we did in middle winter
at 5am.  Running out of Kings Cross & up to Peterborough was like travelling
with our own ARC lights!!!!

AV

>