In message , at 11:39:51 on Fri, 6 Jul 2018,
Anna Noyd-Dryver remarked:
Roland Perry wrote:
In message , at 11:50:20 on Thu, 5 Jul 2018,
Anna Noyd-Dryver remarked:
Roland Perry wrote:
In message , at 09:58:26 on Thu, 5 Jul 2018,
Graeme Wall remarked:

Just when you thought it couldn't get any worse…

https://www.bbc.co.uk/news/uk-england-london-44721415

I smell a rat.

It's extremely unlikely that Network Rail has experienced the
simultaneous failure of three separate incoming grid feeds, nor would it
take all day to get just one of them re-instated.

This sounds like the *Network Rail* equipment which merges the three
feeds into the supply to the signalling centre has gone up in smoke.

Any other electricity supply issues reported overnight in Stretham?


Presumably you’re referring to the tweet referenced in that article
“Passengers are advised not to travel from the South into London this
morning due to total loss of signalling power that Network Rail has
experienced on 3 separate supplies in Streatham area.”? I see no
suggestion that it’s external rather than railway-internal power supplies
which have failed.

It's one signalling centre which is without power, thus the "three
supplies" must be those for that centre.

Here's another report from Network Rail (via Simon Calder):

"A generator has been sourced to isolate the power feed and is
expected to arrive at the signalling centre later this morning.
Once the generator arrives, the situation will be re-assessed."

Note, not three generators, one for each of hypothetically three
separate sites.

Right, here’s some Actual Facts copied from another forum.

quote
As I understand it, it was loss of all signalling power to Streatham
Junction Remote Interlocking area. Ex-Southern Region area signalling
installations usually have three seperate incoming power supply sources,
but in this case there was a catastrophic failure of a part of common
equipment. Other sources state that NR has had to bypass the equipment in
hard wiring to get it working again, but before it could do that it first
had to determine what had caused the original failure, and also monitor the
temporary setup to make sure a hidden fault didn't reoccur and cause even
more damage.

Apparently the incident is subject to a formal inquiry which will report
back to the NR Board and the DfT.

Edit to add: This just in from GTR journeycheck:

“The electrical supply that maintains this areas signalling system failed.
The failure has been traced to a faulty power supply cable which feeds off
the national grid.”

Well, that must of given the changeover switchgear a good bang
/quote

And from another post in the same place:

“Signal power feed triple redundant 3 input BUT the changeover swiitch
(single point of failure) was what burnt out”

That confirms everything I was saying about the cause, thanks.

It appears to differ from Network Rail's originally announced quick-fix
of generators, unless that's what they used ahead of working out it was
safe to hard-wire one of the two remaining grid feeds.

Thus they still have quite a big project ahead of them - reinstating the
three-way failover equipment (as well as the grid having to make 3/3
rather than 2/3 of the supplies operational).
--
Roland Perry