DfT Study - Low Cost Electrification of Branch Lines

[HSTEd]

Well the DfT paid for a study on the technical issues relating to electrification of lightly used mostly-self-contained branch lines using equipment derived from Tram systems, ~750V DC using a mix of variable-tension equipment and trolley style wiring.

I obtained the final report from this study using the Freedom of Information and it should be appearing presently on the Department for Transport website (according to the email letter I received with the document).

Before then I will give you a basic summary of the contents as I think its quite interesting.
Basically they are assuming no more than two electric trains per hour in each direction on a "lightly used" branch line, and that each train should have a maximum power consumption of roughly ~500kW, and the study assumes the use of a light-rail tram-train.
(Myself I would be interested to see if you could use heavy rail vehicles perhaps similar to the Class 456 and whether the installation of at-seat electrical supplies and air conditioning would take it over that, as its currently ~370kW as is. This would avoid the perception of a "second class" service and would be undoubtedly superior in terms of passenger comfort to the vehicles it would be replacing.)

It also discusses the use of wooden poles (similar to those used by utility companies) to support the OHLE which would be simply buried in the ground to allow rapid and low cost installation, with the use trolley wiring or hybrid low cost wiring as required. This is apparently done on the 50kV Black Mesa coal line in the US.

The Hybrid wiring they discuss is not that much more expensive than trolley wiring and would allow operation up to 75mph whereas trolley wiring is apparently restricted to approximately ~50mph.

The report also provides two costed estimates for example branch lines, those being the Atlantic Coast Line (with through-running to St Austell on the Cornish Main Line) and the Looe-Liskeard line with costs (excluding rolling stock) coming to approximately £10 million and £4.8 million respectively, this is apparently significantly cheaper than the electrification used on the main line which this report estimates at close to double that including all the things you need secondary to the actual wiring.

Overall a very interesting report and I encourage you to either request it yourself (ES-2010-003 "Low Cost Electrification of Branch Lines") or wait for it to be released, as it is not an in-house DfT report but was produced by "Delta Rail" I am not entirely sure who owns the copyright and whether I am allowed to put a copy up here.

 

[boing_uk]

I was mulling over lightweight structures for overhead catenary while thinking about the south fylde line the other day. On the WCML, alot of the original structures look like angle iron joined in a lattice with rebar, which is very similar to the Lattix sign post structure we use on highways.

Now Lattix is fairly cheap and can support a reasonable amount of weight on it (a large road sign has a significant wind load) and it got me to thinking whether something like Lattix could be used for the support structures for the overheads, particularly when combined with a screw-pile foundation.

 

[ian959]

Low cost electrification = Don't let Network Rail anywhere near the project!

 

[Trog]

That is all the railway network needs non standard electrification to go with non standard couplings. Why not bring back the broad gauge while they are at it.

 

[asylumxl]

Low cost electrification = Don't let Network Rail anywhere near the project!

Can't imagine it to be any worse than the ECML electrification.

 

[AlterEgo]

That is all the railway network needs non standard electrification to go with non standard couplings. Why not bring back the broad gauge while they are at it.

I don't see the problem. With the Renaissance of branch lines in this country, I think it's a good idea, provided such schemes are limited to lines which are mainly self-contained.

 

[route:oxford]

Why bother with the overhead wires?

Could always go for the Bombardier Primove system with induction circuits buried underneath the track.

http://www.bombardier.com/files/en/supporting_docs/image_and_media/products/PRIMOVE.wmv

http://www.bombardier.com/files/en/supporting_docs/BT-ECO4-PRIMOVE.pdf

It's what should be running down "The High" in Oxford.

 

[rail-britain]

I don't see the problem. With the Renaissance of branch lines in this country, I think it's a good idea, provided such schemes are limited to lines which are mainly self-contained.

That is probably the scope of the scheme, where there is no overlap or likely to be overlap in the future with traditional OHLE
Presumably the main benefit would be the reduced costs in clearance for bridges and other structures, where at the moment bridges are raised and/or track bed is lowered, but with such a scheme the wire could simply be engineered into the existing structure (nil clearance)

 

[HSTEd]

Unless you really think lines like the Atlantic Coast Line or the Far North Line are ever going to be electrified at 25kV in the normal course of things......

Hell you could probably make the argument for electrifying everything west of Plymouth like this as Cornwall is full of branch lines and I don't see main line electrification going west of there any time soon.
Main Line trains could continue to run on the line using diesel traction under the wire so Im not sure how its a bad thing.

EDIT:
With regards to the 'Primove' system the report specifically considers it and rejects it on grounds that the capital cost of installation on existing systems is considered to be huge as you have to dig up the entire trackbed to place the equipment.

It also occurs to me that if you don't like 750V OHLE you could always have "lightweight" 750V third rail on these routes if they are fully segregated.

 

[Class172]

What about electrifying the Stourbridge town branch, it could even use 3rd rail.

 

[Schnellzug]

Only trouble is, would each line need dedicated stock and maintenance facilities, etc? That'd surely work out rather expensive. If you had a number of lines (e.g. in Cornwall) all using the same system, you could order a batch of stock for all of them, but you wouldn't be able to move them between lines on the main line under their own steam, so you'd still have small, isolated fleets scattered all over the place.

 

[HSTEd]

Well thats why I suggested you electrify the Cornish Main Line too..... but the proposal talks about having one electrical control centre for multiple lines using advanced SCADA technologies for reduced cost, and you would probably only need one diesel loco to move the sets up and down since its only what? 70 miles from the St Ives Branch to the Tamar Branch LIne/

 

[Flying Snail]

Well thats why I suggested you electrify the Cornish Main Line too..... but the proposal talks about having one electrical control centre for multiple lines using advanced SCADA technologies for reduced cost, and you would probably only need one diesel loco to move the sets up and down since its only what? 70 miles from the St Ives Branch to the Tamar Branch LIne/

All the added complexities inherent in using non-standard systems for small isolated branches seem to me are the perfect argument for leaving these branch lines diesel operated. The benefits for such lines of electrification are pretty slim in the first place.

 

[Greenback]

All the added complexities inherent in using non-standard systems for small isolated branches seem to me are the perfect argument for leaving these branch lines diesel operated. The benefits for such lines of electrification are pretty slim in the first place.

It raises questions about maintenance, both for the infrastructure and the units used if the line sinvolved are isolated. In my view, it would certainly add costs and complexity to the operation of such lines.

 

[HSTEd]

All the added complexities inherent in using non-standard systems for small isolated branches seem to me are the perfect argument for leaving these branch lines diesel operated. The benefits for such lines of electrification are pretty slim in the first place.

There is the argument that electric trains are normally considered vastly superior to diesel ones by the travelling public and that the deployment of electric trains on these routes would trigger increased passenger numbers which could help the lines potentially reach the point of economic viability.

There is no simple answer to this question, especially once you consider the potential for future rises in the price of diesel oil and so on.

EDIT: The Atlantic Coast Line has access to a TMD at St Blazey, especially if an understanding could be achieved with DB Schenker, likewise the Penzance TMD is almost available to the St Ives Branch, and you would probably want to wire into Penzance anyway to permit Penzance-St Ives services to occur under electric traction.

 

[apk55]

What about trolley wire electrification at 25KV AC? The only extra cost of putting wires up would be larger insulators, plus possibly some work on clearances. It would then be possible to use normal stock, (possibly with an extra pantograph) which could also run on other lines for through services or access to depots

If 750V DC is used there would also be other costs nobody has mentioned

1/ Power supply. Substations are required on DC lines at frequent intervals. For third rail systems with heavyweight conductor rails the approximate distances are 1.5 miles with a 4MW load and 3 miles with a 2MW load. This may be increased for lighter loads, but light weight overhead will reduce the distance and I doubt that substation distances of more than about 6 to 8 miles would be possible even with low powered units. And to supply these substations expensive HT power lines from a bulk supply point would be required, not a problem in urban areas but may be an expensive problem in rural areas where many of these lines are located. In contrast if high voltage AC is used a line could be end fed for at least 15 miles from a single substation and it may be possible to run larger more powerfull trains, even locomotives.

2/ Getting train back to depot. If a train can not run back to the depot and a loco is required to haul it dead this will increase costs considerably and make considerable operational inconveniences. (In addition the maintenance depots will require facilities for powering up and testing DC equipment)

3/ Inter running on main lines. Many of the possible candidates for trolley wire electrification could involve running on a main line as part of the journey, so AC throughout would be advantageous or else dual voltage stock would be required. Some examples I can think of are
a/ Preston Ormskirk
b/ Windermere Branch where there are some through trains from the south
c/ Ipswich Lowestoft Norwich where both ends have AC electrification.

 

[HSTEd]

What about trolley wire electrification at 25KV AC? The only extra cost of putting wires up would be larger insulators, plus possibly some work on clearances. It would then be possible to use normal stock, (possibly with an extra pantograph) which could also run on other lines for through services or access to depots

If 750V DC is used there would also be other costs nobody has mentioned

1/ Power supply. Substations are required on DC lines at frequent intervals. For third rail systems with heavyweight conductor rails the approximate distances are 1.5 miles with a 4MW load and 3 miles with a 2MW load. This may be increased for lighter loads, but light weight overhead will reduce the distance and I doubt that substation distances of more than about 6 to 8 miles would be possible even with low powered units. And to supply these substations expensive HT power lines from a bulk supply point would be required, not a problem in urban areas but may be an expensive problem in rural areas where many of these lines are located. In contrast if high voltage AC is used a line could be end fed for at least 15 miles from a single substation and it may be possible to run larger more powerfull trains, even locomotives.

2/ Getting train back to depot. If a train can not run back to the depot and a loco is required to haul it dead this will increase costs considerably and make considerable operational inconveniences. (In addition the maintenance depots will require facilities for powering up and testing DC equipment)

3/ Inter running on main lines. Many of the possible candidates for trolley wire electrification could involve running on a main line as part of the journey, so AC throughout would be advantageous or else dual voltage stock would be required. Some examples I can think of are
a/ Preston Ormskirk
b/ Windermere Branch where there are some through trains from the south
c/ Ipswich Lowestoft Norwich where both ends have AC electrification.

The report addresses most of these concerns, AC electrification has trouble balancing all three phases of the domestic high tension supply while a DC rectifier will always be balanced across them, this is not much of a problem on a long main line where you can engineer it to overall balance out, or in an urban suituation with a "strong" local network, but in a rural area it could cause all sorts of power distortion problems requiring additional infrastructure work at great cost.

The Atlantic Main Line example noted in the report would have five substations for its entire 25 mile length (including the section to St Austell) and would be engineered to allow any one station to fail without requiring alterations to the service pattern. A Half hourly service in each direction would only require a maximum of four units to be drawing power at once, assuming the track allowed this producing a total power load of only 2MW with the aforementioned 500kW limitation on each unit.

The report considered the implimentation of 25kV but decided that the lack of lightly built multiple units that use that voltage would restrict the choice of suppliers, as would the specialist nature of the equipment required as there are far fewer uses for a 25kV AC supply than a 750V DC one.
The report emphasised the neccesity that the equipment used be off the shelf, and opted for more lower power substations for this reason.
Again on the ACE example the probable TMD at St Blazey would be right on top of one of the substations which should provide the DC power required for testing and maintenance purposes.

I really wish I could put the report itself up by like I said, I am unsure as to its copyright.

EDIT: Also there is no reason to believe that existing dual voltage designs could not use the 750V with fairly minor modifications, as all that would be required would be a pair of contactors that could isolate the pan from the AC traction supply and then short the line to the third rail shoe with it.
That is assuming the units could be made to function on only ~500kW.

 

[Xenophon PCDGS]

After their recent "brainwave", I am dreading news of these proposals reaching the ears and eyes of the Harrogate Chamber of Commerce TOC, who will no doubt be at the media forefront with their prognostications and demands for EU finance for the project.:roll:

Of course. this will have to wait until their current plans for the new Harrogate space shuttle station launch area (which have storage capacity for redundant London Underground tube train units) are finalised.

 

[HSTEd]

After their recent "brainwave", I am dreading news of these proposals reaching the ears and eyes of the Harrogate Chamber of Commerce TOC, who will no doubt be at the media forefront with their prognostications and demands for EU finance for the project.:roll:

Of course. this will have to wait until their current plans for the new Harrogate space shuttle station launch area (which have storage capacity for redundant London Underground tube train units) are finalised.

Luckily we wont have to worry about this any time soon, as a half hourly service in each direction with two car multiple units is probably worse than what they have now.


Ofcourse if you did do everything west of Plymouth you would probably have to create a "South West Electrics" mini-TOC to operate all those services, with the only FGW services remaining being through trains from London to Penzance and Newquay.

EDIT: We are looking at something like a very slightly underpowered Class 158 at most, perhaps a better example would be an air conditioned electric Class 150? If you want Im pretty sure you can fairly easily make them dual voltage as that could come in handy in future or allow a batch order to be made available for some of those routes above, although most of those arent really "self contained"

 

[Kneedown]

All the added complexities inherent in using non-standard systems for small isolated branches seem to me are the perfect argument for leaving these branch lines diesel operated. The benefits for such lines of electrification are pretty slim in the first place.

Electrification is ALWAYS beneficial. It's just the initial costs that can be eye wateringly expensive.
The cost of diesel fuel is high and will only keep getting higher. Maintenance of diesels is costlier too as it more labour intensive, and with more parts that need replacing more often.
Electrifying branch lines will still see a return on the investment, it may just take a little longer. I personally believe that loss making lines would eventually become profitable over a period of time if someone were to bite the bullet and put some wires up or get a third rail down.
--- old post above --- --- new post below ---

EDIT: We are looking at something like a very slightly underpowered Class 158 at most,

We're halfway there then as 158's are already underpowered!

 

[Schnellzug]

Of course, while Electric trains are smooth, fast, quiet & green (where would the power come from, incidentally? Self contained renewable supplies, or taken from the national grid from power stations burning imported coal?), the other side of the coin is that, well, electrification, overhead electrification at any rate, doesn't seem to be very reliable, does it? In fact, right now, there's a new thread on the subject of Wires down at Roydon again! Would these low cost ideas for lightweight catenary be able to cope with a good gale blowing in off the Atlantic, say?

 

[HSTEd]

Well this "hybrid" OHLE design has apparently survived winter storms at wherever it was It was erected (I cant remember now :\ ) and we have trolleypole wiring all over the place these days so that doesn't seem to be much of a problem.

 

[Greenback]

Of course, while Electric trains are smooth, fast, quiet & green (where would the power come from, incidentally? Self contained renewable supplies, or taken from the national grid from power stations burning imported coal?), the other side of the coin is that, well, electrification, overhead electrification at any rate, doesn't seem to be very reliable, does it? In fact, right now, there's a new thread on the subject of Wires down at Roydon again! Would these low cost ideas for lightweight catenary be able to cope with a good gale blowing in off the Atlantic, say?

The fact that electrical power is preferable to diesel cannot be argued. It is the method of electrification that is open to debate.

Maybe in the future the case for conventinal electrification might be overwhelming.

 

[boing_uk]

We really should not be going down the road of bespoke systems for small lines - it really just creates another maintenance headache and reduces the interoperability with the rest of the network.

Rather than looking at wholly new types of infrastructure, we really need to be looking at providing existing infrastructure in a better (or less gold-plated) way. Cheapest doesnt always necessarily mean its the best; we may be engineering our way out of a cheaper option in the future. Branch lines dont need engineering to the same high standard as main lines - if striking a balance between service frequency, stopping patterns and infrastructure capabilities means monetary savings can be made without too much cost on the service, then that has to be a way forward.

 

[Schnellzug]

The fact that electrical power is preferable to diesel cannot be argued. It is the method of electrification that is open to debate.

Maybe in the future the case for conventinal electrification might be overwhelming.

That might well be true if the power could be obtained from regenerative sources locally; then perhaps they could have a genuinely carbon-neutral, with power produced locally. But if they're just going to take it from the regular National Grid, that'll just mean more electricity used, and therefore more Carbon produced in generating it. The idea of a self-contained local carbon-neutral demonstration installation might be worth pursuing, though; it could go withn the idea of 'micro-franchising' these branches and running them on a purely community basis. Just as long as that doesn't completely isolate them form the national network.

 

[Greenback]

We really should not be going down the road of bespoke systems for small lines - it really just creates another maintenance headache and reduces the interoperability with the rest of the network.

Rather than looking at wholly new types of infrastructure, we really need to be looking at providing existing infrastructure in a better (or less gold-plated) way. Cheapest doesnt always necessarily mean its the best; we may be engineering our way out of a cheaper option in the future. Branch lines dont need engineering to the same high standard as main lines - if striking a balance between service frequency, stopping patterns and infrastructure capabilities means monetary savings can be made without too much cost on the service, then that has to be a way forward.

I think this is pretty close to my own views!

That might well be true if the power could be obtained from regenerative sources locally; then perhaps they could have a genuinely carbon-neutral, with power produced locally. But if they're just going to take it from the regular National Grid, that'll just mean more electricity used, and therefore more Carbon produced in generating it. The idea of a self-contained local carbon-neutral demonstration installation might be worth pursuing, though; it could go withn the idea of 'micro-franchising' these branches and running them on a purely community basis. Just as long as that doesn't completely isolate them form the national network.

It may be worth looking into local schemes in conjunction with community based franchises, but I'm not convinced that the overall benefits outweigh the potential disadvantages such as isolation.

I'm positive towards community rail operations, with a local, multi skilled workforce, but such enterprises must continue to be part of a network.

 

[b0b]

The South Shore line here in Chicago seems to have cheapish 25kv but seems to work ok, though it's a fairly low frequency line, so it sounds a good idea to me

http://www.flickr.com/photos/73784413@N00/3350166689/

Edit: turns out it's 1500V DC

 

[ainsworth74]

The South Shore line here in Chicago seems to have cheapish 25kv but seems to work ok, though it's a fairly low frequency line, so it sounds a good idea to me

How many pantographs does one train need!

 

[HSTEd]

Even if the 750V overhead catenary is a bit dodgy I think the idea of that "hybrid" overhead equipment with the ~75mph top speed is a very good one, there are plenty of lines I can think of that would benefit from electrification at 25kV with that top speed (or even less), such as filling in the gaps on the Norwich-Liverpool route that wont be filled by the Midland Main Line electrification project.

EDIT: Just switching to buried telephone poles instead of the current steel masts with either piled or concrete foundations apparently saves going on £76000 per single track kilometre according to the breakdowns in the report, Im trying to work out a cost per track kilometre of doing the "hybrid" catenary at 25kV.

#2: There is apparently some trouble with the overhead wiring causing an overturning moment on buried poles, however it occurs to me that on double track lines (such as Grantham-Nottingham) the poles could be placed between the tracks and be used to support both lines if they can withstand the weight of both sets of equipment as this would balance the forces, or even that you could use two poles supporting some form of wooden gantry.

Edit #3: I have now completed my calculations, if we assume the "hybrid" catenary is simialr to the existing catenary apart from not having tensioning equipment or midpoint anchors and that buried wooden poles are used, the total cost of the electrification comes out at roughly £225,390 per single track kilometre.
This is assuming a mainline grade electrical power supply using booster transformers which I believe may have been deprecated as standard practice in the UK but will do for our purposes.
If this is a twin track route and it is possible to place the supports between the tracks and use one pole to support both sets of equipment, the price goes down to roughly £436,800 per route kilometre. ( This includes removal of duplicated SCADA and Telecomms immunisation budgets)

There are ofcourse further savings that can be made by reducing the capability of the power supply to account for the use of multiple unit trains that will have at most 3000hp (an electrodiesel Class 221 or similar) rather than a 6400hp Class 91 or 92, but I havent got figures to quantify those savings.

Unfortunately probably not low enough to appease the Harrogate Chamber of Commerce people (£30 million for electrification of the full 62km route and ~£150 million for 30 new five car Electric multiple units would bring it to £180 million, more than the £150 million they budget for the 'District Line to Harrogate' plan, but far more capable ).... but there might be some other people who could afford that.

 

[b0b]

How many pantographs does one train need!

It is funny to see the angst of testing 12 car/3 pan 350s on the WCML, compared to this much cheaper ohle