Class 331 white light on roof

[csvt2004]

I have just seen a 4-car class 331 unit on a Skipton-Leeds service and noticed a white light on the roof near the pantograph. Does anyone know what the light is for?

[iands]

Possibly illumination for the "pan camera".

[jim.snowdon]

1 hour ago, iands said:

Possibly illumination for the "pan camera".

They are fitted to a lot of modern electric units, as far as I am aware, to illuminate the pantograph for the on board camera.

 

Because dewirements and entanglements normally result in major delays, and costs, there is a huge incentive for the TOCs to be able to prove that the cause of any incident was due to a defect in the OLE and not their train.

 

Jim

[Wickham Green]

......... but why on earth does the light stay on when a Thameslink ( 700 ) unit's running on the third rail ? ( Alternately, why are the pickup shoes not floodlit too ? )

[jim.snowdon]

12 minutes ago, Wickham Green said:

......... but why on earth does the light stay on when a Thameslink ( 700 ) unit's running on the third rail ? ( Alternately, why are the pickup shoes not floodlit too ? )

Why bother introducing another complication - it's simpler just to run it straight off the unit auxiliaries, so if the unit is on, so is the light. Their all LED lights anyway these days, so it doesn't represent a significant load.

 

And for shoegear - the answer is that when a conductor rail defect takes the shoes off a train, the train doesn't usually wreck the conductor rail in the process, so the defect is still there when you track back up the line and find the pile of collector shoes. OLE is rather on the delicate side by comparison.

 

Jim

[The Stationmaster]

On Class 387s the pan lights go out a short while after the doors have been opened at a station and then go back on when the doors have been closed and power is applied.  The GWR 387s (an no doubt many other more recent units) also have a low level 'ditch light' illuminating the track and adjacent infrastructure a short distance ahead on the 6 foot side- presumably for the forward facing camera?

[DY444]

1 hour ago, Wickham Green said:

......... but why on earth does the light stay on when a Thameslink ( 700 ) unit's running on the third rail ? ( Alternately, why are the pickup shoes not floodlit too ? )

 

Aside from it being easier to keep it on the pan can become damaged anywhere not just when running on AC.  The infamous Kentish Town incident occurred because the pan of a 377/5 collected some overhanging foliage somewhere on the Brighton Line. 

[Sprintex]

Or when it fails to descend before going into the tunnel section from Drayton Park to Moorgate on an old 313 as happened when my mate was a guard on them 

 

Had to go back, pick it up off the trackside, and manhandle it into the carriage.

 

 

Paul

[ColinK]

DRS’s class 88s have the pan light too.  But I don’t know if the light goes out when they are on diesel power.