OLE Equipment Lifespan?

[ic31420]

So I was sitting on platforms 13/14 a Manchester Piccadilly idlely gazing at the OLE uprights, Spans and fixings.

It struck me that some of these along with much of the WCML stuff must be getting on for 40 or so years old and some of them seem to be a bit scabby.

What sort of life span do these things have and have we seen a renewal program of BR era OLE stanchions etc?

 

[AM9]

Some of the GEML OLE gantries are over 70 years old, despite being refitted once with higher voltage insualtors and more recently, rewired completely.

 

[GRALISTAIR]

It struck me that some of these along with much of the WCML stuff must be getting on for 40 or so years old and some of them seem to be a bit scabby.

North of Weaver Jct was done early 70s so 50 years old. South of there 50s 60s so 60 years old

 

[59CosG95]

The MML was done in the early 80s, and the southern ECML in the late 70s, so they're both around 40-45 years old now. Some of the structures on the Hertford Loop have started failing (poor ground conditions IIRC) so new structures have had to be put in to replace them.

 

[LSWR Cavalier]

How long are the wires? How many years do they last? Are they checked and replaced after a certain time?

I understand that the collectors on the pantographs are of softer material. How often are they replaced?

 

[nlogax]

The MML was done in the early 80s, and the southern ECML in the late 70s, so they're both around 40-45 years old now. Some of the structures on the Hertford Loop have started failing (poor ground conditions IIRC) so new structures have had to be put in to replace them.

Going by what's visible from the M6, those structures in the Lake District and border area are definitely showing their age, mostly cosmetically with the occasional mast that looks like it'd prefer to sit down for a bit, given the chance. Hardly surprising since they've been out in extremely exposed areas for multiple decades.

 

[AM9]

How long are the wires? How many years do they last? Are they checked and replaced after a certain time?

I understand that the collectors on the pantographs are of softer material. How often are they replaced?

Some of the conductor wires on the GEML I believe, survived from their installation around 1949 through until the major replacement in the last 20 years. There are still a few stretches of original style wiring (identifiable by their compound catenary configuration) in the Stratford area, but given the very high levels of traffic there they might have had some replacments like for like in the intervening years. The reason that these wires have survived so long is mainly due to them being sized for 1500VDC with it's much higher currents.

 

[A0wen]

So I was sitting on platforms 13/14 a Manchester Piccadilly idlely gazing at the OLE uprights, Spans and fixings.

It struck me that some of these along with much of the WCML stuff must be getting on for 40 or so years old and some of them seem to be a bit scabby.

What sort of life span do these things have and have we seen a renewal program of BR era OLE stanchions etc?

Doesn't some of the Hadfield / Glossop line still have some of the headspans etc from the 1500v DC Woodhead electrification ? That was completed in 1954.

 

[snowball]

What about the Manchester-Altrincham (now Metrolink) line? Does it still have some original supports and gantries from 1931?

 

[LNW-GW Joint]

How long are the wires? How many years do they last? Are they checked and replaced after a certain time?
I understand that the collectors on the pantographs are of softer material. How often are they replaced?

The fast lines of the WCML were rewired during WCRM in the 2000s, both to support 125/140mph and for longer life.
The power supplies were also renewed over most of the route, and apparently the electrical infrastructure was in a poor state after 40 years or so.
But most of the original steel gantry/cantilever structures are still there, as they are on the GEML and places like Manchester-Altrincham (now carrying Metrolink wires).
The deterioration of the WCML infrastructure in the 1960s-90s has been blamed on excessive wear and tear caused by the electric locos (particularly class 86).

 

[edwin_m]

The deterioration of the WCML infrastructure in the 1960s-90s has been blamed on excessive wear and tear caused by the electric locos (particularly class 86).

Track definitely, but power supply and OLE too?

 

[59CosG95]

Track definitely, but power supply and OLE too?

Not sure on the supply of power to the OLE, but certainly physical wear & tear on the contact wire would be affected.

 

[Watershed]

Doesn't some of the Hadfield / Glossop line still have some of the headspans etc from the 1500v DC Woodhead electrification ? That was completed in 1954.

The steelwork is virtually all original once you get past Ardwick Junction. There's quite a few 4 track portals on sections that are now just 2 track.

 

[59CosG95]

The steelwork is virtually all original once you get past Ardwick Junction. There's quite a few 4 track portals on sections that are now just 2 track.

Most of the registrations are original too - the only changes (IIRC) have been the insulators (throughout) to 25kV, and a small section of Mk3 (not sure which subtype) in the Guide Bridge area (the reg arms & insulators look noticeably different). There are no 'headspans' as such on that route either AFAIK.

 

[AM9]

Most of the registrations are original too - the only changes (IIRC) have been the insulators (throughout) to 25kV, and a small section of Mk3 (not sure which subtype) in the Guide Bridge area (the reg arms & insulators look noticeably different). There are no 'headspans' as such on that route either AFAIK.

Interesting you mentioning the headspans (or lack of them on the ex-1500VDC lines). As far as I know, there weren't any. The only type of headspans in the UK seem to be the taut 'cats cradle' type used on 25kV OLE where the top wire is tensioned to be level. The DC OLE tended to use solid gantries for spanning multiple tracks.
Headspans on the 1500VDC continental (French/Dutch) lines often have very high masts with the top wire of the headspan drops sharply from the masts. Thus by design the load hangs from the masts rather than being supported by a headspan that would need very high tension. That would be easier to construct masts for without needing mast buttresses.

 

[59CosG95]

Interesting you mentioning the headspans (or lack of them on the ex-1500VDC lines). As far as I know, there weren't any. The only type of headspans in the UK seem to be the taut 'cats cradle' type used on 25kV OLE where the top wire is tensioned to be level. The DC OLE tended to use solid gantries for spanning multiple tracks.
Headspans on the 1500VDC continental (French/Dutch) lines often have very high masts with the top wire of the headspan drops sharply from the masts. Thus by design the load hangs from the masts rather than being supported by a headspan that would need very high tension. That would be easier to construct masts for without needing mast buttresses.

Have you got any pics of the French/Dutch DC systems? Germany and Austria were very keen on headspans during their elektrifizierung programmes - although in Germany, they're now being replaced by TTCs and (rare for the country) portals. (Some have recently appeared at the northern throat of Ulm Hbf, and in the stations at Friedrichshafen (Stadt) and Aulendorf.) Portal structures in Austria are rare as hen's teeth too - I only recall seeing them on the northern approach to Innsbruck Hbf.
Germany seems to favour lattice masts, and Austria pre-cast concrete too; additionally, Austria still use the brown ceramic insulators (which we stopped using a while ago due to them having a tendency to shatter when damaged), and Germany have only just started to use polymeric ones.
The headspans out there don't even have the diagonal tubes - the steady arms of the contact are affixed via a drop bracket to the lower span wire, while the catenary is suspended from insulators on the middle span wire. See this example at Köln West. (Sometimes the catenary insulators go above the middle span wire, necessitating additional insulators in the middle span wire between tracks - see here at Kufstein)

 

[apk55]

Outside my house in Altrincham are some 90+ year old OLE posts that date back to the original MSJ&A electrification. While the electrification system has changed twice (and the wires and insulators replaced) the basic metalwork is original. Most of the OLE structures used on the Metrolink Altrincham line are the original MSJ&A ones with very few being replaced and mainly due to reasons other than failure. The same also apples to the south juction viaduct line to Cornbrook.

 

[AM9]

Have you got any pics of the French/Dutch DC systems? Germany and Austria were very keen on headspans during their elektrifizierung programmes - although in Germany, they're now being replaced by TTCs and (rare for the country) portals. (Some have recently appeared at the northern throat of Ulm Hbf, and in the stations at Friedrichshafen (Stadt) and Aulendorf.) Portal structures in Austria are rare as hen's teeth too - I only recall seeing them on the northern approach to Innsbruck Hbf.
Germany seems to favour lattice masts, and Austria pre-cast concrete too; additionally, Austria still use the brown ceramic insulators (which we stopped using a while ago due to them having a tendency to shatter when damaged), and Germany have only just started to use polymeric ones.
The headspans out there don't even have the diagonal tubes - the steady arms of the contact are affixed via a drop bracket to the lower span wire, while the catenary is suspended from insulators on the middle span wire. See this example at Köln West. (Sometimes the catenary insulators go above the middle span wire, necessitating additional insulators in the middle span wire between tracks - see here at Kufstein)

It's really difficult finding shots that show the knitting clearly because on those taken from above the wires blend into the ballast and other paraphenalia on the ground. Here's a picture of the DB OLE through a suburban station in Koln. You can see just above the centre of the picture the drape of the headspans from what must ber a 20m+ above rail height mast:
picture of suburban DB station showing headspans across tracks

I can't find any useful pictures of French 1500VDC OLE except with the long single horizontal beams. Some are 'balanced' on top of a single mast!
Looking for Dutch info, I stumbled across thie document on proposals to up the current 1500VDC to 3000VDC using existing infrastructure as a minimum cost option, but with worthwhile enregy savings and performance improvement:
Analysing the business case for introducing a 3 kV traction power supply in Dutch railways
Lots of info there that is relevant to the 3rd rail debate.
Otherwise I can't find any pictures of cable-only spans over DC lines. Maybe I'm remembering it wrong.

 

[LSWR Cavalier]

Overhead wire equipment is somehow 'unglamorous' but I find it fascinating, one wonders how it is planned and maintained at complicated locations, that must be a lot of work.

Sommerfeldt.de has some very good pictures of working catenary for model railways.

 

[Bald Rick]

What wears in the OLE system is if that has mechanical wear due to movement. This is principally the contact wire, and the tension system (pulleys, weights etc). The structures just need an occasional paint, if they are not galvanised. Older insulators suffer frost damage, and are often replaced.

The OLE kit at Stratford is approaching its 72nd birthday in service. In theory a simple replacement of th3 contact wire would keep it going for a few more decades, however the nature of the system (compound construction with auxiliary wire, fixed tension) is much less reliable and requires more maintenance, and is thus a performance risk. Hence it is being replaced as the final part of the GE retiring project.

 

[CW2]

In the West Coast Route Modernisation project the use of headspans for electrification was generally prohibited. It's fine when it's working, but if you suffer a dewirement then there is a good chance the whole lot will get pulled down, blocking not just the line that suffered the failure but everything around it as well. That's why the Trent Valley 4-tracking was all portals and cantilevers. We learned from the errors made by electrification of the ECML on the cheap.

 

[AM9]

Overhead wire equipment is somehow 'unglamorous' but I find it fascinating, one wonders how it is planned and maintained at complicated locations, that must be a lot of work.

Sommerfeldt.de has some very good pictures of working catenary for model railways.

I've always been fascinated by pantographs and OLE, ever since I travelled on the Shenfield electrics in the '50s. Previous to that all I had been on was Central Line underground, the Shenfields were a lot smoother.
I commuted on the GEML when it was being upgrades from 6.25kV to 25kV between Mountnessing and Liverpool St, interesting seeing the (relatively few) modifications to the original 1500VDC wiring to safely accommodate the full 25kV ac. Mainly changing the 'cup and saucer' insulators for shortish multi ribbed ones and adjusting some of the bridge clearances. As Bald Rick says, the last bits of the original knitting is about 72 years old. There's a lot more copper in that than the stringy stuff thats being put up on new schemes.

 

[59CosG95]

I've always been fascinated by pantographs and OLE, ever since I travelled on the Shenfield electrics in the '50s. Previous to that all I had been on was Central Line underground, the Shenfields were a lot smoother.
I commuted on the GEML when it was being upgrades from 6.25kV to 25kV between Mountnessing and Liverpool St, interesting seeing the (relatively few) modifications to the original 1500VDC wiring to safely accommodate the full 25kV ac. Mainly changing the 'cup and saucer' insulators for shortish multi ribbed ones and adjusting some of the bridge clearances. As Bald Rick says, the last bits of the original knitting is about 72 years old. There's a lot more copper in that than the stringy stuff thats being put up on new schemes.

Indeed; the new contact wire is all alloy, either CuSn (Copper & Tin) or CuAg (Copper & Silver). The catenary is now 'Bz II' (CuMg - Copper & Magnesium; the cable being a group of 19 strands of Bz II wire, each 2.1mm in diameter), replacing the earlier AWAC (Alumo-Weld Aluminium Composite) catenary with its propensity for galvanic corrosion, and straight copper catenary (Bz II uses less copper for roughly the same benefit). Bz II is also used when headspans' span wires have to be renewed/replaced as the legacy CdCu (Cadmium & Copper) alloy ones posed health risks on account of, well, cadmium being pretty toxic.
In the new UKMS system (and Series 2 I believe), the lower tension (11kN) contact has a 107mm^2 cross-section, while the higher tension (15kN) has a 120mm^2 cross-section (and is always CuAg).

 

[LNW-GW Joint]

OHLE can be photogenic, and mesmerising at times!
Two pictures of the newish OHLE at Graz Hbf, which I thought was rather neat (2016).

 

[59CosG95]

Two pictures of the newish OHLE at Graz Hbf, which I thought was rather neat (2016).

View attachment 99078 View attachment 99079

They certainly are! Cantilevered structures like the ones in the second picture are absolutely everywhere in Europe, I've noticed. Wonder why they're basically non-existent here?
(I've seen similar ones around the Cheriton end of the Channel Tunnel, and between Canary Wharf & Abbey Wood on the parts of Crossrail that are above ground - I believe Alstom did the design for the OLE so the equipment has a distinctly French feel to it)

 

[WiredUp]

To the OP, nominal lifespans for new UKMS equipment being installed on the network now are:

• 80-120 years - Foundations, structural steelwork, main conductors and ancillary conductors;
• 60 years - Insulators, small part steelwork, tubes, fittings, anti-climb guards & protective screens, tensioning devices;
• 50 years - Contact wire, in-span components, discrete sectioning devices, isolators/ switches, bonding & signage;
• 20 years – Earthing & bonding rail connections.

Mk GE structures have been reused and band-aided for the GEFF upgrade. Some of the oldest unmodified equipment is the Mk1 equipment (60years+ old), much of the SPS in places is covered in Verdigris and doubtless much of the equipment around places like Crewe hasn't seen much if any changes since it was installed.

 

[ic31420]

Thanks for the updates.

I was mildly concerned about some of the steelwork.i saw, I'll grab a snap next time.