OHLE and 3rd Rail

[Judge Dread]

10800 - agreed.

 

Suzie - do you know anywhere on the web where Holcombe Brook is described in detail; I only came across it in an old RM recently, and it looks like a fascinating little station/branch?

 

Kevin

This is strange to put it mildly, just posted about my own layout(s) and the very next posting concerns another layout I had some input with.

Holcombe Brook & Tottington was a layout that was acquired by Steve1 and given to the East Riding Fine Scale Group of which I am a founder member. We revamped it and sold it to "Savoyard" of this parish. You will fine more details at  www.lydcc.org.uk/main.html  On the first photograph, yours truly is just in sight on the far left, masked by the fascia board. 

Incidently the prototype was a branch which was electrified with overhead wiring and then converted to side contact third rail at 1200 volts DC.

[Nearholmer]

JD

 

It was actually the prototype, rather than your absolutely excellent layout, which I found in Railway Modeller c1952, and being a bit of a DC electrification buff, I got all interested, especially when Suzie mentioned 3.5kV and I followed up and read about the Dick Kerr tests. I'm now going on a hunt through contemporary engineering trade journals, because the 3.5kV installation must be described properly somewhere.

 

When I saw the RM article, I thought: Why on earth has nobody ever built a layout of that? Well, now in know they have, and jolly well too!

 

Kevin

[10800]

If you were unaware, we (Re6/6 and myself) are building Balcombe in a universe that retained the overhead in the small yard for operational purposes ...

[Pandora]

The Angerstein Wharf branch near Charlton SE London,  the rather old track diagram, ( it had a look and style  of being from  the 1930s)   in the S&T Relay Room showed Overhead Electrification,  I do not know if the Overhead was ever erected.

 

 

https://en.wikipedia.org/wiki/Angerstein_Wharf

[nick_bastable]

The Angerstein Wharf branch near Charlton SE London,  the rather old track diagram, ( it had a look and style  of being from  the 1930s)   in the S&T Relay Room showed Overhead Electrification,  I do not know if the Overhead was ever erected.

 

 

https://en.wikipedia.org/wiki/Angerstein_Wharf

 

Snowdown colliery kent

 

http://railwayherald.com/imagingcentre/view/150219/LC

 

 

Nick

[iands]

As my first choice of Drayton Park has already been highlighted, does this count?

 

In a sea of 3rd rail DC in and around New Cross Gate (both ELL and NR infrastructure), a 25kV AC test facility at New Cross Gate depot.

 

Regards, Ian.

 

[Nearholmer]

Fascinating.

 

Is that OLE energised, or a section of dead wire on which to test the mechanics of pantographs?

 

K

[Suzie]

I am quite puzzled that the East London was not upgraded to 25KV AC when it underwent conversion from Underground with the 3rd rail changeover then being at New Cross and New Cross Gate.

[caradoc]

I am quite puzzled that the East London was not upgraded to 25KV AC when it underwent conversion from Underground with the 3rd rail changeover then being at New Cross and New Cross Gate.

 

Would that have been possible through the Thames Tunnel ? Plus, East London line trains only run to Highbury & Islington anyway so the proportion of the route with 25kV OLE would still have been relatively small, with the added complication of every train having to be dual voltage and the time taken for the changeovers.

[iands]

Fascinating.

Is that OLE energised, or a section of dead wire on which to test the mechanics of pantographs?

K

It is only energised when a dual voltage unit is required to be tested. IIRC in 'notch 1' only to check the pantograph and current drawn.

 

Regards, Ian.

[Suzie]

Why terminate at Highbury and islington? Last time I went through there I don't recall the whole train empting out - it was just a stop! It is not a logical terminus like Richmond.

[iands]

I am quite puzzled that the East London was not upgraded to 25KV AC when it underwent conversion from Underground with the 3rd rail changeover then being at New Cross and New Cross Gate.

In railway terms, the concept for the ELL was to extend the commuter services from the south to the City and beyond, with a 'through service' that negated the need for passengere to change trains enroute. As 25kV didn't already exist in the New Cross Gate area, it made no sense introducing a change-over point(s) on the route as this would have introduced too much delay into the timetable, which for a metro style operation would have defeated the object of providing a frequent service.

 

 

Regards, Ian.

[iands]

Why terminate at Highbury and islington? Last time I went through there I don't recall the whole train empting out - it was just a stop! It is not a logical terminus like Richmond.

The reason the whole train didn't empty out is that some passengers change at Cannonbury from NLL services to go south, but at certain times of the day it is impossible to get a seat, so they go back one stop to H&I where the train terminates where they are guaranteed to get a seat. H&I is the logical place for a terminus of this sort as it connects with 3 other passenger service lines.

 

Regards, Ian.

[Edwin_m]

I think the concern was that running too many through services onto the NLL would lead to operational disruption on one route spreading to the others.  The ELL can reach Highbury & Islington on separate tracks alongside the NLL and although it is theoretically possible for ELL trains to join the NLL there, the connection is single track and not electrified so only really useable by engineering trains.  For similar reasons the other end of the ELL doesn't work through onto the WLL at Clapham Junction, attractive though the idea of a continuous "outer circle" might be on paper. 

[iands]

I think the concern was that running too many through services onto the NLL would lead to operational disruption on one route spreading to the others.  The ELL can reach Highbury & Islington on separate tracks alongside the NLL and although it is theoretically possible for ELL trains to join the NLL there, the connection is single track and not electrified so only really useable by engineering trains.  For similar reasons the other end of the ELL doesn't work through onto the WLL at Clapham Junction, attractive though the idea of a continuous "outer circle" might be on paper.

 

To re-iterate a comment I posted previously, the single track "Transfer Line" at H&I IS electrified with both DC & AC. But you are correct, there would be significant difficulties creating enough train paths to make it viable to extend ELL services westwards, when there is already a good NLL service going that way.

 

Not sure what the "similar reasons" are at Clapham, other than the ELL stock is DC only, thus making a continuous "outer circle" impossible without either providing DC on the NLL route or providing the entire 378 fleet as dual voltage. How ever these options may seem reasonable engineering solutions, the other important factor is economics -the business case didn't stack up.

 

Regards, Ian.

[Edwin_m]

To re-iterate a comment I posted previously, the single track "Transfer Line" at H&I IS electrified with both DC & AC. But you are correct, there would be significant difficulties creating enough train paths to make it viable to extend ELL services westwards, when there is already a good NLL service going that way.

 

Not sure what the "similar reasons" are at Clapham, other than the ELL stock is DC only, thus making a continuous "outer circle" impossible without either providing DC on the NLL route or providing the entire 378 fleet as dual voltage. How ever these options may seem reasonable engineering solutions, the other important factor is economics -the business case didn't stack up.

 

Regards, Ian.

 

I think the concern at Clapham is that the West London run through a lot of flat junctions and busy freight traffic on the North London Line and the East London encounters similar on the Southern, and they don't want operational disruption on the one to affect the other as it would with a through service.  The extra cost of making the entire fleet dual voltage is quite small, given that they all have the relevant fittings to run on either or both systems, and the saving in units from fewer terminus layovers on a joined-up would probably pay for it. 

[roythebus]

I'd suggest the reason the SR don't want 25kv is the cost of immunising vast areas of signalling and the additional disruption that would cause. Look at Clapham Junction, ok, the WLL trains run into platforms 1-3 or whatever is left, next to the Windsor lines. But that signalling is done with the SWML, which is next to the Central division signalling, so 12 running lines' worth of immunisation for what distance? Plus the yard of course.

[iands]

I'd suggest the reason the SR don't want 25kv is the cost of immunising vast areas of signalling and the additional disruption that would cause. Look at Clapham Junction, ok, the WLL trains run into platforms 1-3 or whatever is left, next to the Windsor lines. But that signalling is done with the SWML, which is next to the Central division signalling, so 12 running lines' worth of immunisation for what distance? Plus the yard of course.

Good point well made. However, the cost of immunisation in such a scenario would be borne by the "project" (which would have been TfL in the case ELL) and not by "SR", but I get the point you are making.

 

Regards, Ian.

[RJS1977]

Another example of overhead electrics and 3rd rail side by side - Reading (Platforms 4,5,6 3rd rail for Waterloo services, 7 upwards in the process of 25kV overhead electrification).

 

There are almost certainly some examples in the Liverpool area where Merseyrail runs close to WCML overhead electrification.

 

And, for a different type of 3rd rail, various locations round the DLR (Shadwell, Limehouse, Stratford, and - at a pinch - Stratford International, with Custom House coming soon. 

 

Also all stations from Bromley by Bow to Upminster on the District line (though C2C trains don't stop at all of them).

[jim.snowdon]

Good point well made. However, the cost of immunisation in such a scenario would be borne by the "project" (which would have been TfL in the case ELL) and not by "SR", but I get the point you are making.

Regards, Ian.

It's not just the issues of signalling immunisation but also the conflicts between the earthed traction return used on the AC electrification and the floating (non-earthed) return of the DC electrification and the risk that one system will create an earth leakage, ie stray current, path for the other.

 

Jim

[GoingUnderground]

I am quite puzzled that the East London was not upgraded to 25KV AC when it underwent conversion from Underground with the 3rd rail changeover then being at New Cross and New Cross Gate.

Apologies for being late to the party, but would there have been sufficient clearance in the Brunel built tunnels under the Thames for OHLE?

 

Back to places where both methods of electrification co-exist, IIRC, there was a stretch on the NLL between Camden Road and Primrose Hill which had both 3rd rail for the Watford to Broad Street service via Primrose Hill, and the link to the NLL freight roads ftom the WCML.

 

Willesden Junction is rather unusual as before conversion to OHLE of the NLL, there was OHLE on the WCML, including on the chord to the NLL that runs alongside the low level station, 3rd rail on the high level NLL ex-Broad Street to Richmond, and "4th rail" on the Bakerloo/Watford DC lines. I've called it "4th" rail as the centre conductor rail which is used by the LU 72 Stock Bakerloo Line services is bonded to the running rails, unlike the rest of the LU system which uses split potential.

 

Is there anywhere else that has 3rd and 4th rail and 25kV OHLE?

[Nearholmer]

Stratford, the DLR being third rail.

[GoingUnderground]

Stratford, the DLR being third rail.

True, I'd forgotten about Stratford, it's not an area with which I'm familiar as I've only passed through on Eurostar. The DLR is 3rd rail but not conventional 3rd rail in that the conductor is raised above ground level. But thanks for the heads up.

 

I suppose Highbury & Islington could also be included, but the 4th rail Victoria Line is undergound, so that's cheating. But on that basis you could also include Euston with the Northern & Victoria lines.

 

But the OP was really about OHLE and conductor rail electrification on the same stretch of track, which is something that I've often wondered about. So thanks everyone, I've enjoyed reading your posts.

[Edwin_m]

Stratford did have top contact third rail in the past as well as OLE and fourth rail, from when the North London Line was electrified until it was converted to DLR.  For some of that time it also had the DLR bottom-contact third rail system on the route via Pudding Mill Lane.  The OLE has also been electrified at 1500V, 6.25kV and 25kV so Stratford may hold some kind of record for the most electrification systems to have been used in one place. 

[Lord of Narnia]

There is a short section at Watford Junction to allow class 313s to get to Bletchley back in the day. Think it’s still there.