Damaged Signalling

[cso]

Had an email from TfL just now about signalling damage on the Picadilly Line before they started running trains.

I am sorry for the significant disruption to your Piccadilly line journeys this morning.

A damaged signalling cable in the Hyde Park Corner area was discovered just before trains started running. Services on the entire line were disrupted, and we were unable to run trains through central London while the damaged cable was replaced.

We are working hard to resume a normal service on the line.

I'm intrigued as to how that sort of severe damage would occur and not be noticed as a it deteriorated?

[Chris M]

I expect that it was not long-term deterioration but rather one or a small number of acute incidents.

One, purely hypothetical scenario, that might result in this would be if the cable was not quite secured properly and so moved in the powerful and turbulent air currents caused by passing trains (c.f. the derailment near Mile End) until either the restraint loosened sufficiently or broke and the cable moved into a position where it was hit by one or more trains and damaged, but not in such a way that caused a signal failure.

[rincew1nd]

My initial thought when reading the above was that an engineering train had caused some damage towards the end of engineering hours. I am, of course, speculating; more factual answers are appreciated!

[aslefshrugged]

Trackernet's Replayer function shows that the first trains were running with Heathrow and Cockfosters as the intended destinations right up until they were reversed ay Kings Cross and Hammersmith.

The closure was originally attributed to overrunning engineering works, there were no reported problems Sunday night so it looks as if the damage was done during engineering hours and not detected until after the start of traffic

[tjw]

In my experience if the signalling cables get damaged the first place to look is the PWay dept. I met one bunch that when lighting fires to burn off rubbish they would light them on top of the concrete troughing containing the signalling cable, nice flat space!

[Deleted]

PB13a, PB13b and PB13c signals were failing this morning due to AR track circuit being down yes there was a cable fault but not sure which actual cable was to be at fault

They could of ran trains through the area but it would of been a painfully slow process hence the reason to suspend they did try a couple but on average it took 15mins to get through the Hyde Park area

[rheostar]

Sept 4, 2017 17:18:57 GMT aslefshrugged said:

Trackernet's Replayer function shows that the first trains were running with Heathrow and Cockfosters as the intended destinations right up until they were reversed ay Kings Cross and Hammersmith.

The closure was originally attributed to overrunning engineering works, there were no reported problems Sunday night so it looks as if the damage was done during engineering hours and not detected until after the start of traffic

If there's a late surrender, trains will still come out of the yard with their correct TDs and will run as far as possible with the expectation of the LSP being lifted. Yesterday (Monday) trains were able to get as far as King's Cross and Hammersmith, the closest points to the buffer sections where trains can be reversed.

We quite often get late surrenders of protection (LSP) due to overrunning engineering work, but they're lifted before trains start to run so outside of Service Control and TAC no one knows about them.