Neutral sections - how long are they?

[8ace]

I thought they don't need such sections because it's DC, which is less of an issue to mix between feeders?

Getting stuck in Neutral Sections, while rare, is going to become an even rarer occurrence as batteries and/or bi/tri-modes prevail, as the unit can simply use an alternative power source to get out of the NS.

There are gaps in the third rail at junctions, level crossings or where it changes side. Mulltiple units may have several pick ups so may not be affected. It was a potential problem for locomotives, hence the development of the electro-diesel and before that locos with flywheels.

I have been stranded at West Worthing LC one time (when some pulled the cord as the service didn't call there), it was a single 4 CIG unit - was it just the MBSO that had pick-up shoes?

The issue with AC is the phase differences between different feeds. DC is just voltage, it doesn’t matter. Simplistically put anyway.

I see makes sense thanks.

 

[D6130]

I have been stranded at West Worthing LC one time (when some pulled the cord as the service didn't call there), it was a single 4 CIG unit - was it just the MBSO that had pick-up shoes?

I see makes sense thanks.

No....the MBSO didn't have pick-up shoes. They were attached to the outer bogies of the DTCoLs.

 

[CW2]

Nearest I have come to getting stuck was on the Inverness - Euston overnight back in the 1980s. An 86/2 with load 16 on a horrible wet night, from a standing start at Motherwell. Acceleration was pitiful, with lots of wheelspin. We entered the neutral section at walking pace, and I was sure we were about to get stranded. Amazingly we managed to keep going, and regained power. Bit of a close call.

 

[edwin_m]

There are gaps in the third rail at junctions, level crossings or where it changes side. Mulltiple units may have several pick ups so may not be affected. It was a potential problem for locomotives, hence the development of the electro-diesel and before that locos with flywheels.

Just to clarify, these gaps are bridged by fat cables so the third rail is continuous electrically speaking. Even where feeders have different voltages the resistance of the third rail between them prevents problems arising.

 

[8ace]

No....the MBSO didn't have pick-up shoes. They were attached to the outer bogies of the DTCoLs.

must have been quite unlucky to get stranded then!

 

[Bald Rick]

The current project on the "Poplars" from GWML at Acton up to the WCML is one, and I believe the reason for it not being installed at all on the link from the MML to the Goblin at Junction Road is because it's not possible. Others likely know more.

The line between the MML and Junction Rd Junction hasn’t been electrified because of clearances, and more specifcially how difficult and expensive it will be to achieve the necessary clearances. That and almost nothing electric would use it anyway (essentially ad hoc ECS from the MML to Hornsey, avoiding a St Pancras reversal)

 

[johnr57]

What is the purpose of a neutral section please?

 

[Wyrleybart]

Single pantograph AC electric locomotives sometimes got stuck in neutral sections. The one that comes to mind is the one at Kidsgrove on the up line from Crewe, initially located about a train’s length from the platform signal. With DVTs, the locomotive was at the rear of the train and if the train stopped at the signal it could get stuck. I believe the neutral section was relocated. The modern type can’t be energised.

https://www.avantiwestcoast.co.uk/t...r-trains/railfans/electricity-and-pantographs says

The awkward OHNS that I remember was on the flyover from the Up Coventry down into the junction at Rugby. IIRC they either moved the signal or the Neutral section for that one.

As for getting stuck, a mate of mine was on the last "Little London" 0015 New St - Euston one Saturday morning, travelling to London for a railtour when the class 310 got trapped in an OHNS somewhere near Bletchley. Fortunately it was still joined up BR back then and a handy class 25 waa able to push the AM10 back into action.

 

[Elecman]

What is the purpose of a neutral section please?

To seperate different fed sections of OLE as adjacent feeders are fed from different phases to each other from the National Grid to balance assist in trying to balance the loads overall.

 

[Bevan Price]

DarloRich said:
Has anything ever got stuck in a neutral section


Yes. I can't quote any specific incident but know it has happened.

Happened to me once when everything was loco hauled. Got stuck in neutral section just North of Stafford. Had to wait for following train to creep up to rear of our train and then push us forward a few yards out of the neutral zone. Today it could be a bigger problem if incompatible trains were following each other....

 

[johnr57]

To seperate different fed sections of OLE as adjacent feeders are fed from different phases to each other from the National Grid to balance assist in trying to balance the loads overall.

Many thanks

 

[WAO]

The line between the MML and Junction Rd Junction hasn’t been electrified because of clearances, and more specificially how difficult and expensive it will be to achieve the necessary clearances. That and almost nothing electric would use it anyway (essentially ad hoc ECS from the MML to Hornsey, avoiding a St Pancras reversal)

One for the batteries then!

WAO

 

[zwk500]

One for the batteries then!

WAO

Far and away the most efficient allocation of the available resources.