Transpennine Upgrade : Manchester/Leeds

[Edwin_m]

43 minutes ago, Mike Storey said:

 

The original plan was not to keep any. The 1938-designed GE portals were deployed for a fixed-tension overhead "line", but the new Mark 3a OLE needed longitudinal (and some lateral) variable tensioning, at very great stresses. The pre-existing portals did not prove capable of supporting that without major revision, especially of spacing. I left the project before the bulk of work was complete, and suspect that the use of some existing portals was indeed a stop gap, designed to bring the project in on budget, for now.

 

I am not well informed on the DC portals in the north, but would suspect they would largely need to be located correctly for 25Kv spans.

 

 

I wondered if the tensioning had a bearing on this issue, but decided to keep quiet as fixed tensioning might be worse, because the force in the wires will increase as they try to contract in cold weather.  But perhaps the tension in the variable tensioning arrangement is much higher than the nominal tension in the fixed arrangement?  

 

Any tension issues would be much more severe on tight curves like the one illustrated, because the tension will tend to pull the structure sideways much more than the normal stagger would on straight track.  

Edited February 27, 2021 by Edwin_m

[Mike Storey]

1 minute ago, Edwin_m said:

I wondered if the tensioning had a bearing on this issue.  But I decided to keep quiet as fixed tensioning might be worse, because the force in the wires will increase as they try to contract in cold weather.  But perhaps the tension in the variable tensioning arrangement is much higher than the nominal tension in the fixed arrangement?  

 

It is indeed designed to be higher, as it relies on heavy weights to keep it at a certain tension, and was strung at a pre-stressed length, designed to be the average/ambient temperature. It would need adjusting for the summer and winter. The fixed tension system relied on much thicker "wire" and was strung up at an ambient temperature. That led to a large number of restrictions during hot and very cold weather, but overall it proved reliable enough.

 

The difference between them is that the Fixed Tension system uses heavyweight gantries that bear the weight of the heavier gauge wire, but the Variable Tension system uses much lighter (smaller diameter) gauge wire, that relies constantly on tension spread throughout several miles. Hence the forces acting on the supports are very different.

[Grovenor]

The heavywieght contact wire and catenery used on the original GE and MSW electrifications was required to carry the much larger currents used by the 1500V system and to cope with the contact wire wear caused by use of greased steel contact strips on the pantographs.

Nothing to do with being fixed length or tensioned. Contact wire size on the 25KV is smaller on account of the much lower currents and the much reduced wear when using carbon contact strips. On 25KV the same size contact wire is used on tensioned and fixed designs but the latter are only used in limited low speed areas due to the sag in summer risking dewirement and the high tension in winter risking snapped wires. The structures needed to support the 1500V OLE needed to be stronger than those for the 25KV due to the much greater weight to be supported so have been able to be reused with 25Kv but are getting long in the tooth and probably in need of replacement now. And, of course track layout changes at pretty well all stations and junctions have forced replacement in those areas.

[Mike Storey]

22 hours ago, Grovenor said:

The heavywieght contact wire and catenery used on the original GE and MSW electrifications was required to carry the much larger currents used by the 1500V system and to cope with the contact wire wear caused by use of greased steel contact strips on the pantographs.

Nothing to do with being fixed length or tensioned. Contact wire size on the 25KV is smaller on account of the much lower currents and the much reduced wear when using carbon contact strips. On 25KV the same size contact wire is used on tensioned and fixed designs but the latter are only used in limited low speed areas due to the sag in summer risking dewirement and the high tension in winter risking snapped wires. The structures needed to support the 1500V OLE needed to be stronger than those for the 25KV due to the much greater weight to be supported so have been able to be reused with 25Kv but are getting long in the tooth and probably in need of replacement now. And, of course track layout changes at pretty well all stations and junctions have forced replacement in those areas.

 

I am sorry, but everything to do with being fixed tension DC or auto tensioned AC. The span lengths are different (1600 metres ave as opposed to 1950 metres), there is no need for mid-span anchors on fixed tension and the span end anchors are completely different. These differences would be even more marked in a curving track situation. So the likelihood of being able to re-use fixed tension supports (whatever their condition) in their original positions, for new auto-tensioned OLE to any great degree, other than on plain line, low tangent sites, is minimal. That is less true for very low speed areas.

 

That is before one considers lateral forces, for which DC OLE was simply not designed, albeit it generally has more heft in that regard, simply by virtue of its greater substantial girth, but not necessarily in its foundation. (This is exemplified by the enormous piling needed for the much simpler, but heavier, Mark IV OLE design for the GW). So, again, possibly fine in cuttings and other sheltered locations, notwithstanding the other requirements, but no good whatsoever in exposed positions. It should be recognised that the increase in wires involved in AC OLE (as a total system) increases wind resistance, compared to the simpler DC version, despite the wires being of smaller diameter.

 

We are not discussing here the difference between fixed and auto-tensioned systems both on AC, so that is irrelevant.

 

Edited February 28, 2021 by Mike Storey

[Grovenor]

18 hours ago, Mike Storey said:

I  It should be recognised that the increase in wires involved in AC OLE (as a total system) increases wind resistance, compared to the simpler DC version, despite the wires being of smaller diameter.

 

We are not discussing here the difference between fixed and auto-tensioned systems both on AC, so that is irrelevant.

 

Well you left it to me to mention that the fixed system related to DC. !

 

How doyou calculate an increased wind resistance from the much lighter AC wiring?  What increase in wires?  A substantial part of the argument to change from 1500V to 25kV was the large reduction in the amount of copper to be hung up and hence in the amount of steel needed to hold it up.

Edited March 1, 2021 by Grovenor

[SHMD]

I think a lot of "myths" were created at the time of the Woodhead closure to "exaggerate" certain aspects of 1500Vdc verses 25kVac - depending almost entirely on whether you wanted to close the line or keep it open.

I'm still hearing some of these today!

 

1500Vdc = thicker conductor but less Catenary and Insulators.

25kVac = thinner conductor but more Catenary and Insulators.

 

In modelling terms that's less knitting verses more knitting!

 

(...ducks down and retreats...)

 

 

Kev.

 

[Zomboid]

There can be additional cabling in AC systems - return conductors are not generally used in DC systems, and being connected to the masts near the cess they cause a different set of forces compared to the contact system.

 

I'm not expert, but the two systems are very different, and any suitability of DC masts and gantries for AC applications is purely coincidental.

[Grovenor]

1 hour ago, SHMD said:

I think a lot of "myths" were created at the time of the Woodhead closure to "exaggerate" certain aspects of 1500Vdc verses 25kVac - depending almost entirely on whether you wanted to close the line or keep it open.

I'm still hearing some of these today!

 

1500Vdc = thicker conductor but less Catenary and Insulators.

25kVac = thinner conductor but more Catenary and Insulators.

On 1500V the woodhead had a compound caterary, ie 3 wires per track with plenty of droppers, all 3 wires, all of them thicker and heavier than the 25kV equivalents, all 3 had to be copper to carry the amps. Looking at the images there is does seem to be an earth wire as well linking the structures. The only thing smaller is the insulators.

The 25kV with far less amps to carry only the contact wire is copper, and steel being stronger the catenary can be smaller, and on the Mk2 designs it was simple catenary so only 2 wires rather than 3. So less knitting with 25kV. And the heavier 1500V overhead needed more steel to hold it up. Look at some of the pics on Google images!

[mikejames]

hi

There seems to be a lot of expert knowledge in the design of overhead electric supply systems

in the members here.

would someone be prepared to do a 101 course for the less expert of us??

(or provide a reference for us to study)

 

thanks in advance

mike james

[NittenDormer]

My understanding is that AC allows in-cab and directional lighting. 

[4630]

6 minutes ago, mikejames said:

 

would someone be prepared to do a 101 course for the less expert of us??

(or provide a reference for us to study)

 

thanks in advance

mike james

 

This might be a useful starting point, but I’m sure there are others just as helpful.

 

https://www.bathnes.gov.uk/sites/default/files/sitedocuments/Planning-and-Building-Control/Planning/nr_a_guide_to_overhead_electrification.pdf

 

[Mike Storey]

On 01/03/2021 at 15:20, Grovenor said:

Well you left it to me to mention that the fixed system related to DC. !

 

How doyou calculate an increased wind resistance from the much lighter AC wiring?  What increase in wires?  A substantial part of the argument to change from 1500V to 25kV was the large reduction in the amount of copper to be hung up and hence in the amount of steel needed to hold it up.

 

Well, physics! But the ER DC systems appears to have been quite different to the DC systems used oop north, so I can only comment on what I know, which is the ER system. The amount of string necessary to install AC on the ER was significantly more than its 1938 DC equivalent. Ergo, the greater surface area (not weight, mind you) of the collective wiring (especially concerning the return conductors, but also some of the earthing cables), created a greater wind resistance. I no longer have the calculations from that project, but I recall that the difference was significant. The end result was that lateral forces needed far more attention, as well as all the other considerations I cited.

 

But if there was a difference in the North, then I must defer to others to comment about that.

[kevpeo]

A hopeful sign at the West end of the scheme.

 

https://www.networkrail.co.uk/running-the-railway/railway-upgrade-plan/key-projects/transpennine-route-upgrade/manchester-to-stalybridge/

 

It's a start! Kev.

[Mike Storey]

31 minutes ago, kevpeo said:

A hopeful sign at the West end of the scheme.

 

https://www.networkrail.co.uk/running-the-railway/railway-upgrade-plan/key-projects/transpennine-route-upgrade/manchester-to-stalybridge/

 

It's a start! Kev.

 

It is a good sign that some things are being progressed, but the gist of this appears to be bridge strengthening east of Victoria, and some track renewals at Miles Platting, towards Stalybridge, but little else. It is normal work for increased frequency/weights, but little else. But, as you say, a start.

[jamie92208]

55 minutes ago, Mike Storey said:

 

It is a good sign that some things are being progressed, but the gist of this appears to be bridge strengthening east of Victoria, and some track renewals at Miles Platting, towards Stalybridge, but little else. It is normal work for increased frequency/weights, but little else. But, as you say, a start.

It also mentioned piling for masts for electrification between Victoria and Stalybridge.

 

Jamie

[62613]

16 hours ago, jamie92208 said:

It also mentioned piling for masts for electrification between Victoria and Stalybridge.

 

Jamie

I suppose the new bridges at Queens Road and Oldham Road will need to be installed before the OHE masts. Nothing to stop works carrying on towards Stalybridge in the meantime, I would think

[jamie92208]

38 minutes ago, 62613 said:

I suppose the new bridges at Queens Road and Oldham Road will need to be installed before the OHE masts. Nothing to stop works carrying on towards Stalybridge in the meantime, I would think

I can't see any reason not to get masts up, or at least foundations in. Obviously they wo't string the knitting till it's all done.

 

Jamie

[Mike Storey]

6 hours ago, jamie92208 said:

I can't see any reason not to get masts up, or at least foundations in. Obviously they wo't string the knitting till it's all done.

 

Jamie

 

I doubt they will do masts until the track renewals are done, otherwise double work.

[62613]

37 minutes ago, Mike Storey said:

 

I doubt they will do masts until the track renewals are done, otherwise double work.

That's what I meant. But from, say, Philips Park down to Stalybridge should present no such problems, as all the track work has been done, bridges raised/realigned, and so on

[SHMD]

56 minutes ago, 62613 said:

That's what I meant. But from, say, Philips Park down to Stalybridge should present no such problems, as all the track work has been done, bridges raised/realigned, and so on

 

...signalling renewed, Ashton Moss now Signalbox-less and the junction replaced, Ashton-u-Lyne re-aligned and painted, mast post foundations clearly defined on the ground...

 

 

Kev.

[4630]

Network Rail submitted a Transport and Works Act Order application to the Department for Transport on 31st March 2021 (just as well that it wasn’t submitted 24 hours later ).

 

Details are available here, but in summary the proposals to improve the railway between Huddersfield and Westtown (Dewsbury) include:

 

• Double the number of tracks from two to four along the majority of the railway.
• Upgrading stations at Huddersfield, Deighton, Mirfield and providing a new station at Ravensthorpe.
• Separating sections of the track from each other with a bridge (fly-over) at Ravensthorpe.
• Electrification of the railway from Huddersfield to Ravensthorpe – and right through to Leeds.

Whilst the proposals have been in the public domain for awhile, the submission of a T&W Order sounds like a very positive move forward.

 

[woodenhead]

16 hours ago, 4630 said:

• Electrification of the railway from Huddersfield to Ravensthorpe – and right through to Leeds.

 

Is there anything about electrification Stalybridge to Huddersfield?

 

If not then I guess they want to electrify the locals between Huddersfield and Leeds to go with the similar for Manchester up to Stalybridge and the 802s and Class 68s will continue to bridge the gap as they do now.

[Edwin_m]

I've seen a couple of online presentations on the project from the parties involved, at least one of which opened with a graphic of Saddleworth Viaduct with OLE added.  Clearly someone's looking at it, but policy currently seems to be to treat these projects as separate tranches to be developed and agreed one at a time. 

 

There is at least a stated intention to connect the electrification from Dewsbury to Leeds, which probably makes sense from the technical point of view as it would provide an alternative power feed and probably avoid the need for a second feeder within the section.  The use of bi-modes means that at least some of the through trains will benefit from whatever electrification is done.  

[Mike Storey]

On 02/04/2021 at 16:05, Edwin_m said:

 

 The use of bi-modes means that at least some of the through trains will benefit from whatever electrification is done.  

 

Yes. The trials being conducted in Germany at present, using Battery EMU's (BEMU) recharged every 50 Km or so, with a 10 Km length of OLE, are real and start later this year (between Hennigsdorf and Wittenberge). There is also work by Furrer and Frey on Quick Charging batteries for trains, using lengths of fixed gantry OLE, which will, probably, be incorporated into the trials.

 

So, Discontinuous Electrification is nearly a reality. The key issue, if it works and proves reliable, is how to fit the kit into the UK loading gauge, I suppose, but I can't see that being a great technical issue, just a commercial one.

[jamie92208]

1 hour ago, Mike Storey said:

 

Yes. The trials being conducted in Germany at present, using Battery EMU's (BEMU) recharged every 50 Km or so, with a 10 Km length of OLE, are real and start later this year (between Hennigsdorf and Wittenberge). There is also work by Furrer and Frey on Quick Charging batteries for trains, using lengths of fixed gantry OLE, which will, probably, be incorporated into the trials.

 

So, Discontinuous Electrification is nearly a reality. The key issue, if it works and proves reliable, is how to fit the kit into the UK loading gauge, I suppose, but I can't see that being a great technical issue, just a commercial one.

That might solve the alleged Standedge tunnel  problem. Wires up the bank either side where there is plenty of available power from Heyrod and Thornhill, then battery for the tunnel which is level as it follows the canal. There even used to be water troughs inside it.

 

However  I am surprised that the tunnel is a problem as double track tunnels usually have quite good clearances. Morley isn't seen as a problem, and that was dug many years before the double track at Standedge.

 

Jamie

Edited April 3, 2021 by jamie92208