Fen Line OLE - what's the extra wire?

[59CosG95]

Looking at the Fen Line on Flickr t'other day, I saw that these wires here (see red arrow) are present along all the single line sections of the route.

Are these auto-transformer feeder (aka Auxilary Feeder) wires? Or just the Return Conductor for the other track, insulated from the other RC?

 

[Snow1964]

The return conductor is on the small insulators, usually on outside of pole

Could be a feeder cable (the large insulators are the clue), not sure of this location, a separate circuit from the transformer / switchgear which feeds another track further along, but is using the single track mast at this location

 

[edwin_m]

I seem to recall the supply here is fairly weak, with limitations on number/length of EMUs - has there been an upgrade recently?

Note also the signal leaning outwards, almost certainly due to the ground conditions which caused a dewirement a few years ago when an OLE pole did the same thing.

 

[Elecman]

Not necessarily AT feeder but almost certainly a bare feeder cable

 

[GRALISTAIR]

Not necessarily AT feeder but almost certainly a bare feeder cable

If no bridges in the way certainly would be cheaper imho than insulated and laid in troughs one would have thought?

 

[Bevan Price]

If no bridges in the way certainly would be cheaper imho than insulated and laid in troughs one would have thought?

Wires in troughs would make things easier for metal thieves....

 

[Bald Rick]

It’s a bare feeder.

There’s a feeder station at Kings Lynn, and another at Milton just north of Cambridge. The system must be designed to allow either feeder to be off line, with the other providing back up. Because there’s a lot of single track north of Ely, if the OLE came down anywhere on the single track section when one of the feeders is off line, there would be no power the ‘other side’ of the break from the supply. For example, if Milton is off line, and the wires come down just south of Kings Lynn, there’s would be no power anywhere north of Milton*, including Ely. Hence the bare feeder provides a route for the juice to get round a fault in the OLE.

*it’s not quite as simple as this, as if Milton is offline then the next feeder south can supply north, but it can’t get all the way to KL.