Trimode specification for new intermittent mainline electrification

[Nottingham59]

A large part of the cost of new electrification comes from having to rebuild bridges to provide adequate clearances for 25kV OHLE.

This is my attempt to specify a DBEMU based loosely on the 80X family that would be capable of handling gaps in electrification and therefore allow lines like the Cross-County route from Bromsgrove to Exeter or the Chiltern Mainline to be electrified at much lower cost.

Overall: 5-car DBEMU based on Hitachi IET
Weight: 250T (based on c800)

Absolute maximum speed: 150mph (achieved by c395 in testing)
Max speed on ETCS: 140mph (c395)
Max speed on lineside signalling: 125mph (HST etc)
Power on OHLE: 3.4MW (based on c395)
Battery power: 2.0MW (sufficient to maintain 125mph on level track in still air, but not accelerate to it)
Battery capacity: 100kWh (equal to the kinetic energy of 250T train at 125mph; sufficient to climb the 140m Devon Banks)
Battery duration at full power: 3mins
Diesel: 400kW (sufficient to maintain 70mph indefinitely. Able also to use HVO biodiesel in any proportion)

Range at 125mph: 6 miles plus coasting after battery is depleted
Range at 100mph: 10 miles + coasting (based on 1MW power needed to maintain 100mph; battery duration = 6 minutes)
Range at 70mph: hundreds of miles (limited only by the size of the diesel tank)

A train like this would be able to do Penzance - Aberdeen:
- On diesel to Exeter, using the battery to get over the hills and with the diesel engine running continuously to recharge the battery;
- on intermittent OHLE installed cheaply between Exeter and Derby (dropping the pan for any long gaps, or switching seamlessly to battery for low bridges with non-conducting contact wires);
- then classic OHLE from Derby to Fife;
- using the planned Scottish intermittent OHLE to Aberdeen.

In fact, it might be possible for EMR to reconfigure their 810s to this specfication by dropping three of the four diesel engines and replacing them with battery packs. If they did this, then NR could avoid wiring Syston to Wigston; and from Beeston to Nottingham etc, saving hundreds of millions of pounds in the process.

I was surprised to see how small the diesel engine can be to power the train away from the wires. It doesn't need to deliver the peak power load at times of acceleration. Instead it can deliver the same energy at a steady rate by running continuously to charge the battery. Two 200kW family car diesel engines in each 5-car DBEMU should do the job.

What do you think?

 

[RobShipway]

A large part of the cost of new electrification comes from having to rebuild bridges to provide adequate clearances for 25kV OHLE.

This is my attempt to specify a DBEMU based loosely on the 80X family that would be capable of handling gaps in electrification and therefore allow lines like the Cross-County route from Bromsgrove to Exeter or the Chiltern Mainline to be electrified at much lower cost.

Overall: 5-car DBEMU based on Hitachi IET
Weight: 250T (based on c800)

Absolute maximum speed: 150mph (achieved by c395 in testing)
Max speed on ETCS: 140mph (c395)
Max speed on lineside signalling: 125mph (HST etc)
Power on OHLE: 3.4MW (based on c395)
Battery power: 2.0MW (sufficient to maintain 125mph on level track in still air, but not accelerate to it)
Battery capacity: 100kWh (equal to the kinetic energy of 250T train at 125mph; sufficient to climb the 140m Devon Banks)
Battery duration at full power: 3mins
Diesel: 400kW (sufficient to maintain 70mph indefinitely. Able also to use HVO biodiesel in any proportion)

Range at 125mph: 6 miles plus coasting after battery is depleted
Range at 100mph: 10 miles + coasting (based on 1MW power needed to maintain 100mph; battery duration = 6 minutes)
Range at 70mph: hundreds of miles (limited only by the size of the diesel tank)

A train like this would be able to do Penzance - Aberdeen:
- On diesel to Exeter, using the battery to get over the hills and with the diesel engine running continuously to recharge the battery;
- on intermittent OHLE installed cheaply between Exeter and Derby (dropping the pan for any long gaps, or switching seamlessly to battery for low bridges with non-conducting contact wires);
- then classic OHLE from Derby to Fife;
- using the planned Scottish intermittent OHLE to Aberdeen.

In fact, it might be possible for EMR to reconfigure their 810s to this specfication by dropping three of the four diesel engines and replacing them with battery packs. If they did this, then NR could avoid wiring Syston to Wigston; and from Beeston to Nottingham etc, saving hundreds of millions of pounds in the process.

I was surprised to see how small the diesel engine can be to power the train away from the wires. It doesn't need to deliver the peak power load at times of acceleration. Instead it can deliver the same energy at a steady rate by running continuously to charge the battery. Two 200kW family car diesel engines in each 5-car DBEMU should do the job.

What do you think?

At some point come 2030, you would need to be replacing the diesel engine with battery power so surely it should be a BEMU unit from the start? Discussions about such trains are within many threads with the Speculation area and does include trains from the likes of Penzance to Aberdeen.

 

[43096]

A large part of the cost of new electrification comes from having to rebuild bridges to provide adequate clearances for 25kV OHLE.

This is my attempt to specify a DBEMU based loosely on the 80X family that would be capable of handling gaps in electrification and therefore allow lines like the Cross-County route from Bromsgrove to Exeter or the Chiltern Mainline to be electrified at much lower cost.

Overall: 5-car DBEMU based on Hitachi IET
Weight: 250T (based on c800)

Absolute maximum speed: 150mph (achieved by c395 in testing)
Max speed on ETCS: 140mph (c395)
Max speed on lineside signalling: 125mph (HST etc)
Power on OHLE: 3.4MW (based on c395)
Battery power: 2.0MW (sufficient to maintain 125mph on level track in still air, but not accelerate to it)
Battery capacity: 100kWh (equal to the kinetic energy of 250T train at 125mph; sufficient to climb the 140m Devon Banks)
Battery duration at full power: 3mins
Diesel: 400kW (sufficient to maintain 70mph indefinitely. Able also to use HVO biodiesel in any proportion)

Range at 125mph: 6 miles plus coasting after battery is depleted
Range at 100mph: 10 miles + coasting (based on 1MW power needed to maintain 100mph; battery duration = 6 minutes)
Range at 70mph: hundreds of miles (limited only by the size of the diesel tank)

A train like this would be able to do Penzance - Aberdeen:
- On diesel to Exeter, using the battery to get over the hills and with the diesel engine running continuously to recharge the battery;
- on intermittent OHLE installed cheaply between Exeter and Derby (dropping the pan for any long gaps, or switching seamlessly to battery for low bridges with non-conducting contact wires);
- then classic OHLE from Derby to Fife;
- using the planned Scottish intermittent OHLE to Aberdeen.

In fact, it might be possible for EMR to reconfigure their 810s to this specfication by dropping three of the four diesel engines and replacing them with battery packs. If they did this, then NR could avoid wiring Syston to Wigston; and from Beeston to Nottingham etc, saving hundreds of millions of pounds in the process.

I was surprised to see how small the diesel engine can be to power the train away from the wires. It doesn't need to deliver the peak power load at times of acceleration. Instead it can deliver the same energy at a steady rate by running continuously to charge the battery. Two 200kW family car diesel engines in each 5-car DBEMU should do the job.

What do you think?

I think we need to stop pretending that batteries are a suitable form of power for mainline de-carbonisation. They aren't (they should be a niche application for lighter use lines) and the answer is to do the job properly and get the wires up. I would not be at all surprised if in a few years time there will be some environmental or health crisis about batteries and their contents.

Oh, and why are we basing anything on the IET? It's utterly appalling from almost every perspective: a manufacturer not interested in suppporting customers, trains that are cracking up (literally), abysmal ride quality, high cost, poor quality, poor reliability, poor availability. There is a consistent theme with these trains and we should not be putting any more orders the way of Hitachi.

 

[eldomtom2]

I was under the impression that discontinuous electrification was in practice unsuitable for nonstop operation due to the various requirements for dropping the pan in motion.

 

[YourMum666]

A large part of the cost of new electrification comes from having to rebuild bridges to provide adequate clearances for 25kV OHLE.

This is my attempt to specify a DBEMU based loosely on the 80X family that would be capable of handling gaps in electrification and therefore allow lines like the Cross-County route from Bromsgrove to Exeter or the Chiltern Mainline to be electrified at much lower cost.

Overall: 5-car DBEMU based on Hitachi IET
Weight: 250T (based on c800)

Absolute maximum speed: 150mph (achieved by c395 in testing)
Max speed on ETCS: 140mph (c395)
Max speed on lineside signalling: 125mph (HST etc)
Power on OHLE: 3.4MW (based on c395)
Battery power: 2.0MW (sufficient to maintain 125mph on level track in still air, but not accelerate to it)
Battery capacity: 100kWh (equal to the kinetic energy of 250T train at 125mph; sufficient to climb the 140m Devon Banks)
Battery duration at full power: 3mins
Diesel: 400kW (sufficient to maintain 70mph indefinitely. Able also to use HVO biodiesel in any proportion)

Range at 125mph: 6 miles plus coasting after battery is depleted
Range at 100mph: 10 miles + coasting (based on 1MW power needed to maintain 100mph; battery duration = 6 minutes)
Range at 70mph: hundreds of miles (limited only by the size of the diesel tank)

A train like this would be able to do Penzance - Aberdeen:
- On diesel to Exeter, using the battery to get over the hills and with the diesel engine running continuously to recharge the battery;
- on intermittent OHLE installed cheaply between Exeter and Derby (dropping the pan for any long gaps, or switching seamlessly to battery for low bridges with non-conducting contact wires);
- then classic OHLE from Derby to Fife;
- using the planned Scottish intermittent OHLE to Aberdeen.

In fact, it might be possible for EMR to reconfigure their 810s to this specfication by dropping three of the four diesel engines and replacing them with battery packs. If they did this, then NR could avoid wiring Syston to Wigston; and from Beeston to Nottingham etc, saving hundreds of millions of pounds in the process.

I was surprised to see how small the diesel engine can be to power the train away from the wires. It doesn't need to deliver the peak power load at times of acceleration. Instead it can deliver the same energy at a steady rate by running continuously to charge the battery. Two 200kW family car diesel engines in each 5-car DBEMU should do the job.

What do you think?

The British Rail Class 804

 

[The Planner]

The power supply itself will be the issue. Lots of small pieces of electrification would all need feeders. Something that wouldnt necessarily be needed when joined up.

 

[Nottingham59]

I was under the impression that discontinuous electrification was in practice unsuitable for nonstop operation due to the various requirements for dropping the pan in motion.

For longer unelectrified sections, you can drop the pan automatically at a balise before the wires end. As a failsafe back-up, terminate the wires on an upwards slope so that the pan, if still raised, goes up beyond its permitted range and automatically drops. You need to do this far enough before the first bridge to allow the pan time to drop before the train gets to the obstruction.

For shorter gaps, such as a single low bridge, you can simply use a sliding insultated contact rod to push the electrically-isolated pan down to give mechanical clearance, even if the bridge is too low to give electrical clearance. The train needs to stop taking AC current from the OHLE before the neutral section starts to avoid sparking at the point of transition. It can all be done automatically.

At some point come 2030, you would need to be replacing the diesel engine with battery power so surely it should be a BEMU unit from the start?

These trains would use Hydrotreated Vegetable Oil (HVO) as a renewable biodiesel. Provided that the hydrogen comes from non-fossil sources, it counts as a decarbonised fuel. Far higher energy density than batteries, and much more suitable for long distance running off the wires. See:
https://uk.dbcargo.com/rail-uk-en/n...-in-bid-to-decarbonise-its-operations-5764438

Oh, and why are we basing anything on the IET?

This is just the specification for a train. I'm sure Stadler could build one for us to this specification if we asked nicely.

I think we need to stop pretending that batteries are a suitable form of power for mainline de-carbonisation. They aren't (they should be a niche application for lighter use lines) and the answer is to do the job properly and get the wires up.

Mainline electrification costs £3-£4 million per stk. Perhaps we need to stop pretending that that sort of spending is justified when there are cheaper ways to do it. At the very least, this approach would allow you to save one third of the cost of full continous electrification, by avoiding having to rebuild every low bridge and tunnel along the route.

The British Rail Class 804

== Doublepost prevention - post automatically merged: 8 Jul 2023 ==

The power supply itself will be the issue. Lots of small pieces of electrification would all need feeders. Something that wouldnt necessarily be needed when joined up.

Well for short distances, like a low bridge or a tunnel, or Wigston-Syston, then you could just run an insulated +25kV/0/-25kV cable in the cess to provide electrical continuity.

For longer gaps, sure, you would need a grid feeder for electrified islands. But not that many: at 90mph this train would have a range on battery only of 8 minutes, but running the diesel engine as a range extender would give you 20 minutes, which is 30 miles. This is the distance from Yate to Gloucester or from Cheltenham to Bromsgrove. So you would only have to electrify Cheltenham to the Gloucester triangle to decarbonise the whole of Bristol-Birmingham.

And I note that Tamworth is 15 miles from Birmingham, and 25 miles from Derby. Tamworth high-level could be supplied from the WCML without needing a new grid feeder at all. You could electrify / batterify the whole cross-country route from Bristol to Edinburgh with just one new grid feeder at Cheltenham.

 

[Bartsimho]

For longer unelectrified esections, you can drop the pan automatically at a balise before the wires end, and as a failsafe back-up terminate the wires on an upwards slope so that the pan, if still raised, goes up beyond its permitted range and automatically drops. You need to do this far enough before the first bridge to allow the pan time to drop before the train gets there.

For shorter gaps, such as a single low bridge, you can simply use a sliding insultated contact rod push the electrically-isolated pan down to give mechanical clearance, even if the bridge is too low to give electrical clearance. The train needs to stop taking AC current from the OHLE before the neutral section starts to avoid sparking at the point of transition. It can all be done automatically.


These trains would use Hydrotreated Vegetable Oil (HVO) as a renewable biodiesel. Provided that the hydrogen comes from non-fossil sources, it counts as a decarbonised fuel. Far higher energy density than batteries, and much more suitable for long distance running off the wires. See:
https://uk.dbcargo.com/rail-uk-en/n...-in-bid-to-decarbonise-its-operations-5764438


This is just the specification for a train. I'm sure Stadler could build one for us to this specification if we asked nicely.


Mainline electrification costs £3-£4 million per stk. Perhaps we need to stop pretending that that sort of spending is justified when there are cheaper ways to do it. At the very least, this approach would allow you to save one third of the cost of full continous electrification, by avoiding having to bebuild every low bridge and tunnel along the route.




Well for short distances, like a low bridge or a tunnel, or Wigston-Syston, then you could just run an insulated +25kV/0/-25kV cable in the cess to provide electrical continuity.

For longer gaps, sure, you would need a grid feeder for electrified islands. But not that many: at 90mph this train would have a range on battery only of 8 minutes, but running the diesel engine as a range extender would give you 20 minutes, which is 30 miles. This is the distance from Yate to Gloucester or from Cheltenham to Bromsgrove. So you would only have to electrify Cheltenham to the Gloucester triangle to decarbonise the whole of Bristol-Birmingham.

And I note that Tamworth is 15 miles from Birmingham, and 25 miles from Derby. Tamworth high-level could be supplied from the WCML without needing a new grid feeder at all. You could electrify / batterify the whole cross-country route from Bristol to Edinburgh with just one new grid feeder at Cheltenham.

I could see discontinuous electrification being used for the MML into Sheffield and for any Hope Valley electrification as it has to deal with the Clay Cross Tunnel, Bradway Tunnel, Totley Tunnel and the Cowburn Tunnel and this would save a hell of a lot of cash on these works.

Also with EMR getting Bi-mode units the move to Biodiesel should be the way it is pushed forwards

 

[SynthD]

For shorter gaps, such as a single low bridge, you can simply use a sliding insultated contact rod to push the electrically-isolated pan down to give mechanical clearance, even if the bridge is too low to give electrical clearance. The train needs to stop taking AC current from the OHLE before the neutral section starts to avoid sparking at the point of transition. It can all be done automatically.

Is that done anywhere, worldwide?

 

[43096]

Mainline electrification costs £3-£4 million per stk. Perhaps we need to stop pretending that that sort of spending is justified when there are cheaper ways to do it. At the very least, this approach would allow you to save one third of the cost of full continous electrification, by avoiding having to rebuild every low bridge and tunnel along the route.

Which other countries are doing this with mainline routes? Are they all wrong?

 

[The Planner]

Well for short distances, like a low bridge or a tunnel, or Wigston-Syston, then you could just run an insulated +25kV/0/-25kV cable in the cess to provide electrical continuity.

For longer gaps, sure, you would need a grid feeder for electrified islands. But not that many: at 90mph this train would have a range on battery only of 8 minutes, but running the diesel engine as a range extender would give you 20 minutes, which is 30 miles. This is the distance from Yate to Gloucester or from Cheltenham to Bromsgrove. So you would only have to electrify Cheltenham to the Gloucester triangle to decarbonise the whole of Bristol-Birmingham.

And I note that Tamworth is 15 miles from Birmingham, and 25 miles from Derby. Tamworth high-level could be supplied from the WCML without needing a new grid feeder at all. You could electrify / batterify the whole cross-country route from Bristol to Edinburgh with just one new grid feeder at Cheltenham.

You assume feeding off the WCML isnt detrimental to whats already there. Considering the second Avanti Liverpool is constrained by power issues it might not be that simple.

 

[Nottingham59]

Is that done anywhere, worldwide?

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

"10.6 Neutral sections and low bridges To run OLE under some low bridges, extended versions of the short neutral section have been employed, using an insulated rod or cable instead of the copper contact wire below the bridge. This can be combined with automatic switches to isolate the train’s pantograph so that it can coast beneath the bridge. The clearance between the insulated wire and the bridge deck or arch can then be reduced, in some cases by up to 200mm."

Normally, this is only done for slow moving trains, but I don't see why it can't be done with longer less steeply inclined insulated rods to accommodate faster trains. Perhaps someone can explain what the limits might be? With batteries, there is no risk of stranding if the train comes to a halt. I don't know of specific examples.

 

[InTheEastMids]

The power supply itself will be the issue. Lots of small pieces of electrification would all need feeders. Something that wouldnt necessarily be needed when joined up.

This is an important point as whilst this thread is focused on the rolling stock, it's also an infrastructure challenge. These small sections would all need appropriate grid feeders.

Electric trains impose extremely dynamic loads on power networks, and the need to charge batteries too may just exacerbate that, so grid connections for all these small feeder stations may well be neither quick nor cheap to obtain, especially where the stock will be power hungry

 

[Nottingham59]

You assume feeding off the WCML isnt detrimental to whats already there. Considering the second Avanti Liverpool is constrained by power issues it might not be that simple.

When HS2 opens to Handsacre, there should be plenty of unused capacity on the WCML.

 

[The Planner]

When HS2 opens to Handsacre, there should be plenty of unused capacity on the WCML.

HS2 will be using the WCML feed at Brereton. Those trains are going to drink power like its going out of fashion.

 

[Nottingham59]

This is an important point as whilst this thread is focused on the rolling stock, it's also an infrastructure challenge. These small sections would all need appropriate grid feeders.

Electric trains impose extremely dynamic loads on power networks, and the need to charge batteries too may just exacerbate that, so grid connections for all these small feeder stations may well be neither quick nor cheap to obtain, especially where the stock will be power hungry

Yes. Rather than big 400kV grid feeders, battery islands will need SFC's, which take a balanced three-phase supply and provide a single 25kV phase to the railway. Much less disruptive to the electricity network, so they can use much cheaper grid connections.

These trains will take at most 5.4MW AC; 3.4MW for AC traction and 2MW to recharge the batteries. That's just 200A from a 33kW supply. Double that if you get one in each direction at a time.

Maybe NR should order a fleet of a dozen SFCs able to take power from 33kV power lines and built into 40ft shipping containers so they can be deployed to support batterification, and redeployed elsewhere if a battery route is later fully electrified?

== Doublepost prevention - post automatically merged: 8 Jul 2023 ==

HS2 will be using the WCML feed at Brereton. Those trains are going to drink power like its going out of fashion.

I think there's a grid feed at Tamworth too. At least, there is a 132kV substation called "Tamworth BR" next to the railway there. I don't know how much spare capacity it might have.

 

[Bald Rick]

What do you think?

Genuine question - why would you only have a 100kWh battery? That weighs about half a ton and is the size of a couple of big suitcases. Something 10 times as big is entirely feasible, and enables much more use of the battery. (AIUI, the battery on the 802 trial is going to be more than 1MWh, but I’m happy to be corrected).

I was under the impression that discontinuous electrification was in practice unsuitable for nonstop operation due to the various requirements for dropping the pan in motion.

Dropping the pan in motion is not an issue.

Raising it in motion can be in some circumstances, but there’s relatively simple ways around that, whcih are used daily at various places on the network.

Leaving the pan up when it should be dropped is definitely an issue, as the collection of bits of pantograph next to the Westway bridge testifies. Which is why it needs to be automated.

 

[Energy]

I was under the impression that discontinuous electrification was in practice unsuitable for nonstop operation due to the various requirements for dropping the pan in motion.

There are 2 ways:

1 - Drop the pantograph. This can be done pretty easily at stations or on the move but this requires significant distance. This only makes sense when you have a long section without wires.

2 - Earthing the overhead wire. This let's you leave the pantograph up (there is still a wire so the pantograph won't hit anything) but the wire has no electrical clearance. You also need batteries to supply the train as there won't be a current through the wire.

However now you can use insulating paint which reduces the electrical clearance to be smaller than the mechanical (same advantages as earthing the wire) but keeps the wire live.

Earthed overhead wires also require neutral sections either side and expensive 25kv cables to connect either side or seperate feeder stations.

Over in Wales earthed sections are used in tunnels (the design would have been done years ago, the insulating paint is more recent) and longer sections without wires. Earthed is not a solution for bridges. The neutral section, insulated 25kv wire etc. isn't worth the couple million pounds a bridge replacement is.

For shorter gaps, such as a single low bridge, you can simply use a sliding insultated contact rod to push the electrically-isolated pan down to give mechanical clearance, even if the bridge is too low to give electrical clearance. The train needs to stop taking AC current from the OHLE before the neutral section starts to avoid sparking at the point of transition. It can all be done automatically.

You're describing earthed overhead lines. See my issues with that above.

Mainline electrification costs £3-£4 million per stk. Perhaps we need to stop pretending that that sort of spending is justified when there are cheaper ways to do it. At the very least, this approach would allow you to save one third of the cost of full continous electrification, by avoiding having to rebuild every low bridge and tunnel along the route.

There are better ways to save money, getting rid of stop start electrification programmes and giving suppliers and contractors long term certainty would be a good start.

Genuine question - why would you only have a 100kWh battery? That weighs about half a ton and is the size of a couple of big suitcases. Something 10 times as big is entirely feasible, and enables much more use of the battery. (AIUI, the battery on the 802 trial is going to be more than 1MWh, but I’m happy to be corrected).

Exactly. If we going battery do long-ish distances.

Dropping the pan in motion is not an issue.

Raising it in motion can be in some circumstances, but there’s relatively simple ways around that, whcih are used daily at various places on the network.

It isn't an issue but only makes sense with longer battery sections, not bridge hopping as others have suggested.

 

[Nottingham59]

Genuine question - why would you only have a 100kWh battery? That weighs about half a ton and is the size of a couple of big suitcases. Something 10 times as big is entirely feasible, and enables much more use of the battery.

I calculated that 100kWh was all that was needed on a tri-mode. Remember for this configuration, the main energy store is the biodiesel in the fuel tanks, which has a far higher energy density than any battery. The main purpose of the battery is to smooth out the energy consumption, so that the 400kW diesel engine only has to provide the average power used, which is much less than the peak power requirement.

100kWh is enough to accelerate the consist to 125mph, and re-capture that kinetic energy under braking. Coincidentally it will also get a 250T train from sea level over the 140m Devon Banks, which I believe are the highest unelectrified summits on the cross-country route.

But you do need high power rating to support 125mph running: 2MW is quite a load for a battery. Ideally it needs to recharge at 3-5MW, to accommodate heavy braking. And the battery does need to be able withstand repeated deep discharges: on my Penzance-Aberdeen example, it would get discharged from full to zero at least a dozen times.

(AIUI, the battery on the 802 trial is going to be more than 1MWh, but I’m happy to be corrected).

That's good news. I'd not seen that figure before. What range do they expect to get from that?

If the industry is looking at that size of battery for 802B trains, then it could save itself a fortune in mainline electrification costs.

And from now on, all future electrification schemes should be designed to support extensive batterification of the national fleet: EMUs and 802B for the mainlines; the FLIRT Akku for regional expresses (100mph, 90m range; recharge in 15 minutes); and Class 756s or similar for local services.

 

[Bald Rick]

That's good news. I'd not seen that figure before. What range do they expect to get from that?

The trial is replacing the genset pack on one vehicle only, so range will be an abstract concept.

On the charging cycle - one of the (many) reasons to have a bigger battery is so that it doesn’t do full discharge / charge cycles, as that limits life. This is particularly true for Lithium Ion batteries, but much less so for Lithium Titanate which will generally be used in rail applications.

 

[Trainbike46]

A large part of the cost of new electrification comes from having to rebuild bridges to provide adequate clearances for 25kV OHLE.

This is my attempt to specify a DBEMU based loosely on the 80X family that would be capable of handling gaps in electrification and therefore allow lines like the Cross-County route from Bromsgrove to Exeter or the Chiltern Mainline to be electrified at much lower cost.

Overall: 5-car DBEMU based on Hitachi IET
Weight: 250T (based on c800)

Absolute maximum speed: 150mph (achieved by c395 in testing)
Max speed on ETCS: 140mph (c395)
Max speed on lineside signalling: 125mph (HST etc)
Power on OHLE: 3.4MW (based on c395)
Battery power: 2.0MW (sufficient to maintain 125mph on level track in still air, but not accelerate to it)
Battery capacity: 100kWh (equal to the kinetic energy of 250T train at 125mph; sufficient to climb the 140m Devon Banks)
Battery duration at full power: 3mins
Diesel: 400kW (sufficient to maintain 70mph indefinitely. Able also to use HVO biodiesel in any proportion)

Range at 125mph: 6 miles plus coasting after battery is depleted
Range at 100mph: 10 miles + coasting (based on 1MW power needed to maintain 100mph; battery duration = 6 minutes)
Range at 70mph: hundreds of miles (limited only by the size of the diesel tank)

A train like this would be able to do Penzance - Aberdeen:
- On diesel to Exeter, using the battery to get over the hills and with the diesel engine running continuously to recharge the battery;
- on intermittent OHLE installed cheaply between Exeter and Derby (dropping the pan for any long gaps, or switching seamlessly to battery for low bridges with non-conducting contact wires);
- then classic OHLE from Derby to Fife;
- using the planned Scottish intermittent OHLE to Aberdeen.

In fact, it might be possible for EMR to reconfigure their 810s to this specfication by dropping three of the four diesel engines and replacing them with battery packs. If they did this, then NR could avoid wiring Syston to Wigston; and from Beeston to Nottingham etc, saving hundreds of millions of pounds in the process.

I was surprised to see how small the diesel engine can be to power the train away from the wires. It doesn't need to deliver the peak power load at times of acceleration. Instead it can deliver the same energy at a steady rate by running continuously to charge the battery. Two 200kW family car diesel engines in each 5-car DBEMU should do the job.

What do you think?

A few things that came to mind for me:

- Don't ever specify the manufacturer; While Hitachi would obviously be well placed to respond because of their experience from the 80x, other manufacturers could also respond; Stadler has more experience with BEMUs, and there's nothing to say CAF, Siemens, Talgo or Alstom wouldn't be able to offer such a train
- Definitely don't cancel any of the MML electrification; the units have been ordered (and some have been finished); Changing that would incur significant cost, while reducing the usefulness of the OHLE for freight operations.
- How much electrification and extra batteries would be needed to do away with the diesel engine entirely and significantly simplify the design?

== Doublepost prevention - post automatically merged: 9 Jul 2023 ==

Genuine question - why would you only have a 100kWh battery? That weighs about half a ton and is the size of a couple of big suitcases. Something 10 times as big is entirely feasible, and enables much more use of the battery. (AIUI, the battery on the 802 trial is going to be more than 1MWh, but I’m happy to be corrected).

Exactly; use a bigger battery and avoid all the faff around the HVO (which really isn't that sustainable, so should only be used when other options are not possible; that is simply not the case in rail) and diesel engines

 

[Elecman]

Yes. Rather than big 400kV grid feeders, battery islands will need SFC's, which take a balanced three-phase supply and provide a single 25kV phase to the railway. Much less disruptive to the electricity network, so they can use much cheaper grid connections.

These trains will take at most 5.4MW AC; 3.4MW for AC traction and 2MW to recharge the batteries. That's just 200A from a 33kW supply. Double that if you get one in each direction at a time.

Maybe NR should order a fleet of a dozen SFCs able to take power from 33kV power lines and built into 40ft shipping containers so they can be deployed to support batterification, and redeployed elsewhere if a battery route is later fully electrified?

== Doublepost prevention - post automatically merged: 8 Jul 2023 ==


I think there's a grid feed at Tamworth too. At least, there is a 132kV substation called "Tamworth BR" next to the railway there. I don't know how much spare capacity it might have.

The Tamworth Feeder is disconnected

 

[eldomtom2]

Leaving the pan up when it should be dropped is definitely an issue, as the collection of bits of pantograph next to the Westway bridge testifies. Which is why it needs to be automated.

Yes, and I was under the impression that the length required for a safe automated pantograph-dropping system (I'm having trouble thinking of the right word) was in the order of miles.

And from now on, all future electrification schemes should be designed to support extensive batterification of the national fleet

What precisely do you mean by this? Just making sure there's spare capacity?

 

[Energy]

Yes, and I was under the impression that the length required for a safe automated pantograph-dropping system (I'm having trouble thinking of the right word) was in the order of miles.

Its not a short distance and can't be near busy junctions so can be quite far. Fine for long battery sections but certainly not for hopping underneath bridges.

 

[Snow1964]

Generally speaking dropping pantograph for short distance is bad idea. Easier to have a neutral section balise, before and after the low bridge.

There is common misconception the overhead has to pass under the bridge, cables are suspended and move a bit, but can have a fixed overhead bar too which can be vertically thinner and won't change height with temperature. More of a faff with transitions each end but easier than moving a bridge. Of course the power cable needs to go around the gap to link both sides and finding space for this tends to mean often not practical to avoid raising the bridge.

The other thing is don't want contact wire changing height too much, fine to do it over a reasonable distance, but don't want steep hills in the contact wire and pantograph trying to follow vertical kinks in cable alignment

Of course on most main lines want to get clearance for W10 or W12 whilst doing it, so raising bridges has other advantages.

By time allowed for this, very few obstacles (low bridges) are deemed better to not move than rebuild, especially as prefabricated replacements are nowadays easy to install

The other common misconception is need to install huge masts, yes need rigidity on high speed lines, but these days fairly stock size basic H section or lattice poles are good for 180km/h (110mph) lines, and even more simple version when speeds below 120km/h (75mph). No advantage in using over-engineered expensive overhead on lower speed lines, just wasting money. The good news is there is very little mainline with >110mph line speed remaining unelectrified.

 

[Bald Rick]

Yes, and I was under the impression that the length required for a safe automated pantograph-dropping system (I'm having trouble thinking of the right word) was in the order of miles.

not really. Maybe a mile or so in a difficult place.

 

[Energy]

not really. Maybe a mile or so in a difficult place.

4km (2.5 miles) at 125mph. Of course shorter at lower speeds.

 

[snowball]

The other common misconception is need to install huge masts, yes need rigidity on high speed lines, but these days fairly stock size basic H section or lattice poles are good for 180km/h (110mph) lines, and even more simple version when speeds below 120km/h (75mph). No advantage in using over-engineered expensive overhead on lower speed lines, just wasting money. The good news is there is very little mainline with >110mph line speed remaining unelectrified.

TTCs seem very popular on current electrification schemes, no doubt because they only require one foundation to cover both tracks, but they are more elaborate than STCs. And heavy Series 1 kit seems to be among the mix being used on some schemes.

 

[Bald Rick]

4km (2.5 miles) at 125mph. Of course shorter at lower speeds.

Sorry, yes, I was referring to the “power changeover time” in that diagram (25 sec), which is just less than a mile at 125.

 

[Alfie1014]

Oh, and why are we basing anything on the IET? It's utterly appalling from almost every perspective: a manufacturer not interested in suppporting customers, trains that are cracking up (literally), abysmal ride quality, high cost, poor quality, poor reliability, poor availability. There is a consistent theme with these trains and we should not be putting any more orders the way of Hitachi.

And probably most importantly they are awful accessibility wise high floors and narrow door openings, considering how much of an improvement the MkIII wide doorways were over what had gone before the 800 family is a step backward in so many ways.