Thameslink Class 700

[pigsty]

Not really a modelling question, and I wouldn't normally ask this sort of thing, but as I see the things daily on my way to work ...

 

The new Class 700 that Thameslink uses has an odd feature that I've never seen before.  On the roof of the second and eleventh car of each set (PTSO if you speak train) there's a bright white light, facing towards the middle of the set and mounted at a slight up angle.  As the train comes towards you, you see it first as though another train is following on a different track, and then as a spare light above the group around the driver's cab.  It clearly can't illuminate the way the train is going, and both are always on, so you see another as the train recedes.

 

Whatever is it for?

[Circloy]

The light above the cab is to aid visibility to trackworkers. But as you mention the second and eleventh coach then, assuming PTSO means Pantograph Trailer Second Open, it is possible that it's to illuminate and monitor the pantograph for damage. either caused by faulty overhead wiring, or damage it may cause to the wiring. - Part of the blame and claim culture on the railways now. - The rules are so daft that if a train is delayed due to a bird strike breaking the drivers cab window they have to determine which species was involved to apportion the compensation that arises out of the delay.

 

 

[pigsty]

Ah, now, that could be it.  Where I see them is DC supply so the pantograph is never raised, so I do wonder why the light isn't set to come on only when it is.

[Circloy]

confirmed via builders website

 

http://www.siemens.co.uk/en/thameslink/desiro-city.htm

 

but as to why it appears always on I don't know

 

[Bigdave22014]

The footage can also be used by the OHLE engineers for a visual inspection.

[vandy1]

Pan cameras. The ex TL class 387's also have them. Mandatory fitment on most or if not all 25kv fleets. Mainly used for incidents involving wire down scenarios where it can be proved if it was an OHL issue or a fleet fault that caused an incident. Normally it would take months of evidence gathering that usually meant delay minutes running into millions of pounds are disputed between the TOC and NWR.  

 

Cheers

 

DSJ ( ex Thameslink fleet performance engineer)