OHLE types - amendments and corrections requested

[AidanCroft]

Hello all,

I was wondering about the different OHLE types funnily enough. Can anyone correct/amend/add to my current data -

MK1 - early WCML, imperial measurements, cantilever, painted masts, copper wire/cantilevers, use of portals on multi track, cantilevers on twin track, uses corrosion resistant components

MK2 - Glasgow to Wemyss Bay only, metric measurements, cantilever, unique experiment, now phased out, used cheaper galvanised steel arms

MK3 - ECML and northern WCML, uses headspans, uses cantilevers on twin track, many problems with it, introduced on BedPan, galvanised masts/aluminium arms, simple sagged, auto tensioned, lower system height, higher tension, development of MK2, AWAC catenary

a - steel headspan wires, copper contact
b - ditto but aluminium headspan wires, uses metric components
c - ditto but copper catenary, imperial components
d - copper/tin contact

MK4 - 140mph running, thicker wires, incompatible with MK3, higher tension

UK1 - modification of MK1/MK3 using aluminium or maybe steel cantilever arms and non porcelain insulators, first designed for WCML upgrade

Series 1 - this removed over-boom catenary wire and associated bird and pulley wheel problems!

Series 2 - copper wire, bronze catenary, fixed earthing devices, Omnia aluminium cantilever sliding component arrangement, few components, removed over-boom catenary wire and associated bird and pulley wheel problems




Kind regards,

Aidan.

 

[tadhatter]

This is an interesting topic as OLE has fascinated me since I was a young lad and occasional visits to the wcml
However as a layman I have no idea of the surveying/architectural language you mean.

A few things I've noticed over the years;
Very early type OLE as on fenchurch st. to Shoeburyness and the woodhead route.
Round masts on some southern sections of 2 track wcml such as around Kilsby tunnel.

 

[LNW-GW Joint]

Another thing got me wondering yesterday touring the new GW work near Reading.
The masts in the "country" in the Thames Valley are of fairly light solid square section, much less intrusive that the H-section headspan stuff near Paddington.
However, there is a run of masts of this type alongside the gasholders east of Reading, and they all have two large horizontal portals about a metre apart vertically.
These are of lattice steel construction, and make the whole look extremely top heavy (no wires yet, of course).
There are no portals yet in the "country", but if they have the double portal arrangement they will look very intrusive.
Maybe they just need the extra strength in the station area, but time will tell.

I haven't been north to look at the new EGIP wiring around Glasgow, but from photos it looks like the NW kit also going up now.
It also looks as though autotransformer operation will only be on main lines - it's being installed on Liverpool-Manchester, but not Huyton-Wigan.

And not to forget that there is still some late-1920s-era steelwork holding up the Metrolink catenary between Altrincham and Cornbrook.

 

[swt_passenger]

I was told that the double portals are to deal with all the extra tensioning hardware for starting/finishing all the additional contact wire and catenary wire runs needed for the fan out towards the station throat, and the various running junctions which start some way out of the east end of the station. In other words the gradual transition from a 4 track to a 9 track railway.

 

[LNW-GW Joint]

I was told that the double portals are to deal with all the extra tensioning hardware for starting/finishing all the additional contact wire and catenary wire runs needed for the fan out towards the station throat, and the various running junctions which start some way out of the east end of the station. In other words the gradual transition from a 4 track to a 9 track railway.

Yes that would make sense.
Let's hope they only need one portal normally!

 

[matchmaker]

Glasgow North and the Cathcart Circle will probably be the same as the WCML

 

[Beebman]

Glasgow North and the Cathcart Circle will probably be the same as the WCML

Yes it as, as is much of the Great Eastern suburban and LTSR (with exceptions noted below).

I believe that most if not all of the MK2 OHLE used on the Gourock and Wemyss Bay lines has been replaced by a later type.

The original MK3 installation was on the line between Clapton and Cheshunt via Northumberland Park which was not wired as part of the original Great Eastern project. I believe the type of OHLE used here is just known as 'MK3' with no suffix.

I also believe that MK3d can only be found on the Stockport-Hazel Grove line.

Again I'm not sure, but I think MK4 can only be found on the original section of CTRL at Dollands Moor (i.e. between the NR/Eurotunnel boundary and the start of HS1).

There are some other types not in Aidan's original list:

MSJ&A - this was originally installed between Manchester London Road (Piccadilly) and Altrincham in the 1930s. I don't know how much of the original installation survives but some portals still appear to be in use by both NR and Metrolink.

LNER - two installations:

Manchester London Road (Piccadilly) to Rotherwood (Sheffield) - still survives today between Ardwick and Glossop/Hadfield. There was a mid-60s extension to Tinsley Yard using OHLE of a more modern style but not MK1.

Liverpool Street/Fenchurch Street to Shenfield - mostly modernised by Furrer & Frey but I think the Fenchurch Street 'branch' (via Gas Factory Jct) is still original?

There were 2 DC extensions beyond Shenfield to Southend Victoria and Chelmsford installed by BR in the 1950s. Both used an updated variant of the LNER type but the Shenfield to Chelmsford section appears to have been modernised at the time of AC conversion. I believe that both extensions are due to be modernised by Furrer & Frey (maybe done already?).

(Talking of DC, does the OHLE on the section of NR line used by the Tyne & Wear Metro have a particular designation?)

And finally, the type of OHLE used on the Larkhall branch in Scotland is known as SM1 (S for Siemens). Is this the type used on the Bathgate and Paisley Canal lines and for the MK2 OHLE replacement project?

 

[snowball]

What about Manchester to Glossop and Hadfield that was part of the 1950s Woodhead route and later converted to 25kV?

 

[LNW-GW Joint]

There's also the North London line (at least two wirings at different times) and the West London north of the M40.
And the extension from Cornbrook to Trafford Park.
Kidsgrove-Crewe.
Lichfield-Redditch.

 

[Ploughman]

Stockton Darlington on the North Eastern.

 

[Helvellyn]

Any photos for the novices?

 

[AM9]

Yes it as, as is much of the Great Eastern suburban and LTSR ....

....LNER - two installations:

Liverpool Street/Fenchurch Street to Shenfield - mostly modernised by Furrer & Frey but I think the Fenchurch Street 'branch' (via Gas Factory Jct) is still original?

There were 2 DC extensions beyond Shenfield to Southend Victoria and Chelmsford installed by BR in the 1950s. Both used an updated variant of the LNER type but the Shenfield to Chelmsford section appears to have been modernised at the time of AC conversion. I believe that both extensions are due to be modernised by Furrer & Frey (maybe done already?).

I have watched the GE OH installations since I was a child. The original LST-Shenfield wiring was heavy compound catenary with simple catenary for sidings, bay platforms (e.g. Ilford) and Ilford car sheds. The insulators were single disc types. This configuration was also in place on the Southend and Chelmsford extensions just before the line was converted to AC.
On conversion, all the original wiring to Southend and as far as Mountnessing was kept as AFAICR the original insulators were used at 6.25Kv AC. From Mountnessing, where the 25Kv started, the wiring was replaced with something much lighter with cantilevers and full size 25Kv insulators.
Sometime in the '70s, the rules for HV clearance were changed, reducing the minimum clearance for 25Kv from 13inches to something like 6-8inches. With all the transformer issues on the AM5s, the 25Kv was extended all the way in to LST. At that time, it seemed that only the original 1500VDC type insulators were replaced, for 25Kv ones that were shorter and 'stubbier' than those beyond Mountnessing. At the same time, some of the feed points were removed although the ABBs still cycled off at Harold Wood, Chadwell Heath, Forest Gate and I think somewhere near Bow.

I hope that my memory serves me right.

 

[AidanCroft]

Does anyone have any further technical specifications of the standard British Rail and post-BR designs?

Kind regards,

Aidan.

 

[snowball]

AM9's post reminds me that some lines around Glasgow were also converted from 6.25 kV to 25kV - possibly in more than one stage because one half of the Cathcart Circle could not be converted until the introduction of the reduced clearances he mentions.

 

[AidanCroft]

Any more ideas folks?

Kind regards,

Aidan.

 

[AM9]

Any more ideas folks?

Kind regards,

Aidan.

More a question but it may bring forth more information:

When I look at the GE knitting, I see that there is a cable mounted outside the masts/portals on each side. It is secured by small single insulaors, - I have always assumed that this is the ground return cable to remove some of the return currents from track circuits. Loking at currentMML OHLE, I see that there is a similar cable running along from one support to the next but stood above the portals/headers on what look like 25kV insulators. Could this be the 50kV auto transformer feed?

 

[cmovcc]

http://www.rmweb.co.uk/community/index.php?/topic/71391-british-railways-ole-part-one-plain-track/

(lots of other technical posts in the electrification section too)

 

[snowball]

More a question but it may bring forth more information:

When I look at the GE knitting, I see that there is a cable mounted outside the masts/portals on each side. It is secured by small single insulaors, - I have always assumed that this is the ground return cable to remove some of the return currents from track circuits. Loking at currentMML OHLE, I see that there is a similar cable running along from one support to the next but stood above the portals/headers on what look like 25kV insulators. Could this be the 50kV auto transformer feed?

Yes it could and is.

 

[AM9]

Thanks cporter and snowball for the replies.

 

[AidanCroft]

No problems! I've managed to get detailed specifications for each type from Network Rail!!

Kind regards,

Aidan.

 

[Harbon 1]

Okay since we seem to have some experts here (which is good because OHLE has always massively interested me ), I know that the southern part (Euston - Crewe) uses Mk1 OHLE and newer installations are of the Mk3 type, so why is the height between the contact wire and the catenary wire so much less in the newer type, is there a specific reason?

 

[snowball]

Okay since we seem to have some experts here (which is good because OHLE has always massively interested me ), I know that the southern part (Euston - Crewe) uses Mk1 OHLE and newer installations are of the Mk3 type, so why is the height between the contact wire and the catenary wire so much less in the newer type, is there a specific reason?

I'm not an expert but obviously if you can get away with a reduced height difference without ill effects then it will be cheaper.

Mk 1 was compound catenary - the contact wire hangs from a second wire which hangs from a third wire - whereas Mk 3 is simple cantenary (no third wire). At the time Mk 1 was designed they thought compound catenary was necessary to maintain adequate contact between the overhead and the pantograph at speed, but by the time Weaver Junction to Glasgow was done they had found they could get by without it.

 

[Harbon 1]

I'm not an expert but obviously if you can get away with a reduced height difference without ill effects then it will be cheaper.

Mk 1 was compound catenary - the contact wire hangs from a second wire which hangs from a third wire - whereas Mk 3 is simple cantenary (no third wire). At the time Mk 1 was designed they thought compound catenary was necessary to maintain adequate contact between the overhead and the pantograph at speed, but by the time Weaver Junction to Glasgow was done they had found they could get by without it.

Thank you for the answer.

So when they refurbed the wires and did away with the compound catenary, they kept the same height obviously so they didn't have to replace the structures, but when the west coast upgrade was carried out they continued with the bigger gaps, is there a reason or did they just go with the trend?

 

[AM9]

Thank you for the answer.

So when they refurbed the wires and did away with the compound catenary, they kept the same height obviously so they didn't have to replace the structures, but when the west coast upgrade was carried out they continued with the bigger gaps, is there a reason or did they just go with the trend?

The other factor is the change in the clearance requirements for 25kV. This was relaxed in the early '60s. Thus the WC extensions were able to benefit from them but the c1958-1961 wiring is done to the old spec.

 

[L&Y Robert]

What about Manchester to Glossop and Hadfield that was part of the 1950s Woodhead route and later converted to 25kV?

What about Lancaster-Morecabe-Hesham? I remember this being electrified using wooden poles ("Telegraph poles!") at first. Then it was changed to something like the modern cantilever structures. I remember reading that the line had been electrified using three different systems, the latest one was to trial the modern equipment.

And another thing:

When the first AC system was installed, that'd be on Manchester-Crewe, the then write-up in the paper explained that different bits were energised at different voltages, the lower voltage because of the reduced clearances in the urban area. Is that still true? How does the locomotive cope with that?

 

[snowball]

When the first AC system was installed, that'd be on Manchester-Crewe, the then write-up in the paper explained that different bits were energised at different voltages, the lower voltage because of the reduced clearances in the urban area. Is that still true? How does the locomotive cope with that?

Some sections in the suburbs of Glasgow (not on the WCML) and on the lines out of Liverpool Street and/or Fenchurch Street were initially electrified at 6.25kV but later converted to 25kV.

The conversion became possible mainly because the clearance rules were relaxed though it may have involved some structural alterations as well.

 

[AM9]

This thread should be read in conjunction with another recent one:

http://www.railforums.co.uk/showthread.php?t=106509

Auto voltage changeover is discussed and also there is a link to a very good reference document describing the operation of the GE conversion.