London Banter - View Single Post - Network Rail "incorrectly designed" the Gospel Oak

Recliner[_3_] · February 11th 17, 11:30 AM posted to uk.transport.london

On Fri, 10 Feb 2017 07:24:39 -0600,
wrote:

In article , (Graeme
Wall) wrote:

On 10/02/2017 12:22, Anna Noyd-Dryver wrote:
Graeme Wall wrote:
On 10/02/2017 09:54, d wrote:
On Thu, 09 Feb 2017 19:42:06 +0000
Charles Ellson wrote:
On Thu, 9 Feb 2017 16:37:46 -0000 (UTC), Recliner
wrote:

wrote:
On Thu, 9 Feb 2017 16:04:47 -0000 (UTC)
Recliner wrote:
wrote:
The vast majority of freight is hauled by class 66 and 70 diesels
and the main electric freight loco the class 92 can run off 3rd
rail anyway.

The main electric freight loco is the class 90. Class 92s are
little used.

You sure about that? I thought the 90 was a passenger loco that
only occasionally did light freight because its built for high
speed, not pulling power.

When did you last see a class 92 hauling anything? Most electric
freight are hauled by class 90s.

Class 92s tend to be seen with Channel Tunnel traffic, there is no
current reason for them to be preferred over straight 25kV locos away
from such traffic.

So there's no freight on southern region then?

Al diesel hauled round here, which is why they are discussing the
"electric spine" running 25kV from Reading to Southampton.

The problem with electric freight on 3rd rail is that the current drawn
to move a competitive-sized freight at a competitive speed, is very
close to the current at which the circuit breakers trip.

Which is why, I suspect, the 92s were never very useful.

I thought their main problem was electrical interference fed back into the
power supply and signalling systems. I understand this is still being worked
on with solutions hoped for imminently, by Caledonian Sleepers at least.
Their needs are AC only of course.

I think that's right. But the fact that the problem only came to light
with the sleepers indicates just how little the 92s have been used on
25kV main line freights. GBRf thought they were acquiring a mature,
well-proven design, not locos that had mainly been in storage.