The Anonymous Widower

A Selection Of Train Noses

I have put together a selection of pictures of train noses.

They are in order of introduction into service.

Class 43 Locomotive

The nose of a Class 43 locomotive was designed by Sir Kenneth Grange.

Various articles on the Internet, say that he thought British Rail’s original design was ugly and that he used the wind tunnel at Imperial College to produce one of the world’s most recognised train noses.

  • He tipped the lab technician a fiver for help in using the tunnel
  • Pilkington came had developed large armoured glass windows, which allowed the locomotives window for two crew.
  • He suggested that British Rail removed the buffers. Did that improve the aerodynamics, with the chisel nose shown in the pictures?

The fiver must be one of the best spent, in the history of train design.

In How Much Power Is Needed To Run A Train At 125 mph?, I did a simple calculation using these assumptions.

  • To cruise at 125 mph needs both engines running flat out producing 3,400 kW.
  • Two locomotives and eight Mark 3 carriages are a ten-car InterCity 125 train.

This means that the train needs 2.83 kWh per vehicle mile.

Class 91 Locomotive

These pictures show the nose of a Class 91 locomotive.

Note, the Class 43 locomotive for comparison and that the Driving Van Trailers have an identical body shell.

It does seem to me, that looking closely at both locomotives and the driving van trailers, that the Class 43s  look to have a smoother and more aerodynamic shape.

Class 800/801/802 Train

These pictures show the nose of a Class 800 train.

In How Much Power Is Needed To Run A Train At 125 mph?, I did a simple calculation to find out the energy consumption of a Class 801 train.

I have found this on this page on the RailUKForums web site.

A 130m Electric IEP Unit on a journey from Kings Cross to Newcastle under the conditions defined in Annex B shall consume no more than 4600kWh.

This is a Class 801 train.

  • It has five cars.
  • Kings Cross to Newcastle is 268.6 miles.
  • Most of this journey will be at 125 mph.
  • The trains have regenerative braking.
  • I don’t know how many stops are included

This gives a usage figure of 3.42 kWh per vehicle mile.

It is a surprising answer, as it could be a higher energy consumption, than that of the InterCity 125.

I should say that I don’t fully trust my calculations, but I’m fairly sure that the energy use of both an Intercity 125 and a Class 801 train are in the region of 3 kWh per vehicle mile.

Class 717 Train

Aerodynamically, the Class 700, 707 and 717 trains have the same front.

But they do seem to be rather upright!

Class 710 Train

This group of pictures show a Class 710 train.

Could these Aventra trains have been designed around improved aerodynamics?

  • They certainly have a more-raked windscreen than the Class 717 train.
  • The cab may be narrower than the major part of the train.
  • The headlights and windscreen seem to be fared into the cab, just as Colin Chapman and other car designers would have done.
  • There seems to be sculpting of the side of the nose, to promote better laminar flow around the cab. Does this cut turbulence and the energy needed to power the train?
  • Bombardier make aircraft and must have some good aerodynamicists and access to wind tunnels big enough for a large scale model of an Aventra cab.

If you get up close to the cab, as I did at Gospel Oak station, it seems to me that Bombardier have taken great care to create a cab, that is a compromise between efficient aerodynamics and good visibility for the driver.

Class 345 Train

These pictures shows the cab of a Class 345 train.

The two Aventras seem to be very similar.

Class 195 And Class 331 Trains

CAF’s Class 195 and Class 331 trains appear to have identical noses.

They seem to be more upright than the Aventras.

Class 755 Train

Class 755 trains are Stadler’s 100 mph bi-mode trains.

It is surprising how they seem to follow similar designs to Bombardier’s Aventras.

  • The recessed windscreen.
  • The large air intake at the front.

I can’t wait to get a picture of a Class 755 train alongside one of Greater Anglia’s new Class 720 trains, which are Aventras.

 

 

 

 

 

October 14, 2019 Posted by | Transport, Uncategorized | , , , , , , , , | Leave a comment

Thoughts On The Aerodynamics Of A Class 91 Locomotive

The Class 91 locomotive is unique in that it the only UK locomotive that has a pointed and a blunt end.

The Wikipedia entry has external and internal pictures of both cabs, which are both fully functional.

The speeds of the locomotive are given as follows.

  • Design – 140 mph
  • Service – 125 mph
  • Record – 161.7 mph
  • Running blunt end first – 110 mph

The aerodynamic drag of the train is determined by several factors.

  • The quality of the aerodynamic design.
  • The cross-sectional area of the train.
  • The square of the speed.
  • The power available.

The maximum speed on a level track, will probably be determined when the power available balances the aerodynamic force on the front of the train.

But with a train or an aircraft, you wouldn’t run it on the limit, but at a safe lower service speed, where all the forces were calm and smooth.

If you compare normal and blunt end first running, the following can be said.

  • The cross sectional area is the same.
  • The available power is the same.
  • Power = DragCoefficient * Speed*Speed, where the DragCoefficient is a rough scientifically-incorrect coefficient.

So I can formulate this equation.

DragCoefficientNormal * 125*125 = DragCoefficientBlunt * 110*110

Solving this equation shows that the drag coefficient running blunt end first is twenty-nine percent higher, than when running normally.

Looking at the front of a Class 91 locomotive and comparing it with its predecessor the Class 43 locomotive, it has all the subtlety of a brick.

The design is a disgrace.

Conclusion

This crude analysis shows the importance of good aerodynamic design, in all vehicles from bicycles to fifty tonne trucks.

 

If

 

 

October 11, 2019 Posted by | Transport | , | 1 Comment

HS2 Way Out In Front In Tunnel Design For High-Speed Rail

The title of this post is the same as that of this article on Rail Engineer.

The article describes how Arup and Birmingham University are using physical and computer modelling to obtain the ultimate profiles of both tunnel portal and train nose to both increase train performance and reduce train noise as the trains enter tunnels.

They are even using a huge shed at the former British Rail Research Centre in Derby!

The biggest problem, is that there are aerodynamic effects, as the trains enter the tunnels at very high speeds, which result in what are inevitably called sonic booms, that disturb the local residents.

Because the new trains and tunnel portals are being developed together, there must be a greater chance, they will meet the objectives.

Collateral Benefits

Get the design right and there will be other benefits.

Lower Power In The Cruise

In How Much Power Is Needed To Run A Train At 125 mph?, I said this.

I have found this on this page on the RailUKForums web site.

A 130m Electric IEP Unit on a journey from Kings Cross to Newcastle under the conditions defined in Annex B shall consume no more than 4600kWh.

This is a Class 801 train.

  • It has five cars.
  • Kings Cross to Newcastle is 268.6 miles.
  • Most of this journey will be at 125 mph.
  • The trains have regenerative braking.
  • I don’t know how many stops are included

This gives a usage figure of 3.42 kWh per vehicle mile.

This figure is not exceptional and I suspect that good design of the train’s nose will reduce it, especially as the design speed of High Speed Two will be 360 kph or 224 mph.

Reduced Noise

Stand on a Crossrail platform at say Southall or West Drayton stations and listen to the Class 801 trains passing.

They are only doing about 100 mph and they are certainly not quiet! Noise comes from a variety of sources including aerodynamics, overhead wires and running gear.

Could the nose and profile of high speed trains also be designed to minimise noise, when cruising at high speeds?

Reduced Pantograph Noise

Travelling at up to 360 kph, pantograph noise could be a serious problem.

The only way to cut it down, would be to lower the pantograph in sensitive areas and run the train on battery power.

But if the trains energy consumption could be cut to a much lower level, it might be possible for the cruise to be maintained on battery power alone.

Consider a journey between Euston and Birmingham.

  • The train would accelerate away from Euston and go in a tunnel to Old Oak Common.
  • Batteries could be charged whilst waiting at Euston and in the run to Old Oak Common.
  • Accelerating away from Old Oak Common would bring the train to 360 kph as fast as possible.
  • It would now cruise virtually all the way to Birmingham Interchange at 360 kph.
  • At the appropriate moment the pantograph would be lowered and the train would use the kinetic energy to coast into Birmingham Interchange.
  • There would probably be enough energy in the batteries to take the train into Birmingham Curzon Street station after the stop at Birmingham Interchange.

One technology that will massively improve is the raising and lowering of the pantograph at speed.

So could we see much of the long non-stop intermediate section being run on batteries with the pantograph down. If power is needed, it would raise to power the train directly. If the raising and lowering was efficient, then it might be able to use the pantograph only in tunnels.

Could It Be Possible To Dispence With Wires Outside Of Tunnels?

Probably not on the first phase of High Speed Two, but consider.

  • High Speed Two is designed to have a lot of tunnels.
  • Arup and Birmingham may come up with even better aerodynamic designs.
  • Pantograph raising and lowering will get faster and extremely reliable.
  • Battery technology will hold more electricity for a given weight and volume.
  • Dispensing with visible wires could reduce the problems of getting planning permissions.
  • Noise and visible intrision will be reduced.

I believe there will come a time, when high speed railways could be built without visible overhead electrification.

The only places, where electrification would be used would be in tunnels and stations.

Are There Any Other Applications Of This Research?

These are a few thoughts.

Hitachi Trains For The Midland Main Line

I’m suspicious, that the research or similar research elsewhere, might have already produced a very handy result!

In an article in the October 2019 Edition of Modern Railways, which is entitled EMR Kicks Off New Era, more details of the new Hitachi bi-mode trains for East Midlands Railway (EMR) are given.

This is said.

The first train is required to be available for testing in December 2021 with service entry between April and December 2022.

The EMR bi-modes will be able to run at 125 mph in diesel mode, matching Meridian performance in a step-up from the capabilities of the existing Class 80x units in service with other franchises. They will have 24 metre vehicles (rather than 26 metres), a slightly different nose to the ‘800s’ and ‘802s’, and will have four diesel engines rather than three.

Could the new nose have been designed partly in Birmingham?

Consider.

  • Hitachi’s bi-modes for EMR InterCity could be running at up to 225 kph in a few years.
  • The Midland Main Line between Derby and Chesterfield goes through a number of tunnels in a World Heritage Site.
  • Hitachi have collaborated with UK research teams before, including on the Hyabusa.
  • Hitachi and Bombardier are submitting a joint bid for High Speed Two trains, which is based in Birmingham.

It should be noted that when the Tōkaidō Shinkansen opened in 1964 between Tokyo and Osaka average speed was 210 kph.

So are Hitachi aiming to provide EMR InterCity with almost Shinkansen speeds on a typical UK main line?

Arup and Birmingham University, certainly have the capability to design the perfect nose for such a project.

Aventras

Did the research team also help Bombardier with the aerodynamics of the Aventra?

I’m pretty certain, that somebody did, as these trains seem to have a very low noise signature, as they go past.

Talgo

Tsalgo are building a research centre at Chesterfield.

Will they be tapping in to all the rail research in the Midlands?

Conclusion

It looks to me, that there is some world-class research going on in Birmingham and we’ll all benefit!

October 4, 2019 Posted by | Transport | , , , , , , , , , , | Leave a comment

The Batteries For Bombardier Electrostars

This article on the Railway Gazette is entitle Bombardier And Leclanché Sign Battery Traction MoU.

This is the second paragraph.

According to Bombardier, Leclanché will deliver ‘imminently’ its first performance demonstrator battery systems, after which it will be in line to supply traction equipment worth in excess of €100m for use in more than 10 rolling stock projects.

In Stadler’s New Tri-Mode Class 93 Locomotive, I investigated who was providing two large suitcase-sized batteries for Stadler’s new Class 93 locomotive.

In the related post, I said this about the batteries in the Class 93 locomotive, which I describe as a hybrid locomotive.

The Class 93 Locomotive Is Described As A Hybrid Locomotive

Much of the article is an interview with Karl Watts, who is Chief Executive Officer of Rail Operations (UK) Ltd, who have ordered ten Class 93 locomotives. He says this.

However, the Swiss manufacturer offered a solution involving involving an uprated diesel alternator set plus Lithium Titanate Oxide (LTO) batteries.

Other information on the batteries includes.

  • The batteries are used in regenerative braking.
  • Batteries can be charged by the alternator or the pantoraph.
  • Each locomotive has two batteries slightly bigger than a large suitcase.

Nothing is said about the capacity of the batteries, but each could be say 200 litres in size.

I have looked up manufacturers of lithium-titanate batteries and there is a Swiss manufacturer of the batteries called Leclanche, which has this data sheet, that describes a LT30 Power cell 30Ah.

  • This small cell is 285 mm x 178.5 mm x 12 mm.
  • It has a storage capacity of 65 Wh
  • It has an expedited lifetime of greater than 15,000 cycles.
  • It has an energy density of 60 Wh/Kg or 135 Wh/litre

These cells can be built up into much larger batteries.

  • A large suitcase is 150 litres and this volume would hold 20 kWh and weigh 333 Kg.
  • A battery of 300 litres would hold 40 kWh. Is this a large Swiss suitcase?
  • A box 2.5 metres x 1 metre x 0.3 metres underneath a train would hold 100 kWh and weigh 1.7 tonnes

These batteries with their fast charge and discharge are almost like supercapacitors.

, It would appear that, if the large suitcase batteries are used the Class 93 locomotive will have an energy storage capacity of 80 kWh.

I wonder how many of these batteries can be placed under a Bombardier Eectrostar.

It looks rather cramped under there, but I’m sure Bombardier have the detailed drawings and some ideas for a bit of a shuffle about. For comparison, this is a selection of pictures of the underneath of the driver car of the new Class 710 trains, which are Aventras.

It looks like Bombardier have done a big tidy-up in changing from Electrostars to Aventras.

In Battery Electrostars And The Uckfield Branch, I came to the conclusion that Class 387 trains were the most likely trains to be converted for battery operation.

I also developed Excel spreadsheets that model the operation of battery trains on the Uckfield Branch and the Marshlink Line.

AshfordOre

HurstGreenUckfield

Feel free to download and examine.

Size Of Batteries Needed

My calculations in the two spreadsheets are based on the train needing 3 kWh per vehicle-mile to cruise between stations.

To handle the Uckfield Branch, it appears that 290.3 kWh is needed to go South and 310.3 kWh to go North.

I said this earlier.

A box 2.5 metres x 1 metre x 0.3 metres underneath a train would hold 100 kWh and weigh 1.7 tonnes.

So could we put some of these batteries under the train?

The Effect Of More Efficient Trains

My calculations  are based on the train needing 3 kWh per vehicle-mile, but what if the trains are more efficient and use less power?

  • 3 – 290.3 – 310.3
  • 2.5 – 242.6 – 262.6
  • 2 – 194.9 – 214.9
  • 1.5 – 147.2 – 167.2
  • 1 – 99.4 – 119.4

Note.

  1. The first figure is Southbound and the second figure is Northbound.
  2. More power is needed Northbound, as the train has to be accelerated out of Uckfield station on battery power.

The figures clearly show that the more efficient the train, the less battery capacity is needed.

I shall also provide figures for Ashford and Ore.

  • 3 – 288
  • 2.5 – 239.2
  • 2 – 190.4
  • 1.5 – 141.5
  • 1 – 92.7

Note that Westbound and Eastbound energy needs are the same, as both ends are electrified.

I obviously don’t know Bombardier’s plans, but if the train’s energy consumption could be reduced to around 2 kWh per vehicle-mile, a 250 kWh battery on the train would provide enough energy storage for both routes.

Could this be provided by two of Leclanche’s batteries designed to fit a space under the train?

These would be designed to provide perhaps 250 kWh.

What Would Be The Ultimate Range Of A Class 387 Train On Battery Power?

Suppose you have a four-car Class 387 train with 25 kWh of battery power that leaves an electrified station at 60 mph with a full battery.

How far would it go before it came to a lifeless stop?

The battery energy would be 250 kWh.

There would be 20 kWh of kinetic energy in the train.

Ranges with various average energy consumption in kWh per vehicle-mile are as follows.

  • 3 – 22.5 miles
  • 2.5 – 27 miles
  • 2 – 34 miles
  • 1.5 – 45 miles
  • 1 – 67.5 miles

Obviously, terrain, other traffic and the quality of the driving will effect the energy consumption.

But I do believe that a well-designed battery-electric train could easily handle a fifty mile electrification gap.

What Would Be The Rescue Range On One Battery?

One of the main reasons for putting batteries on an electrical multiple unit is to move the train to a safe place for passenger evacuation if the electrification should fail.

This week, there have been two electrification failures in London along, one of which was caused by a failing tree in the bad weather.

I’ll assume the following.

  • The train is a Class 387 train with one 125 kWh battery.
  • The battery is  ninety percent charged.
  • The train will be moved at 40 mph, which has a kinetic energy around 9 kWh.
  • The energy consumption of the train is 3 kWh per vehicle-mile.

The train will use 9 kWh to accelerate the train to line speed, leaving 116 kWh to move the train away from the problem.

With the energy consumption of 3 kWh per vehicle-mile, this would be a very useful 9.5 miles.

Regenerative Braking To Battery On Existing Trains

This has been talked about for the Class 378 trains on the London Overground.

Regenerative braking to batteries on the train, should cut energy use and would the battery help in train recovery from the Thames Tunnel?

What About Aventras?

Comparing the aerodynamics of an Electrostar like a Class 387 train with an Aventra like a Class 710 train, is like comparing a Transit van with a modern streamlined car.

Look at these pictures some of which are full frontal.

It should be noted that in one picture a Class 387 train is shown next to an InterCity 125. Did train designers forget the lessons learned by Terry Miller and his team at Derby.

I wonder how much electricity would be needed to power an Aventra with batteries on the Uckfield branch?

These are various parameters about a Class 387 train.

  • Empty Weight – 174.81 tonnes
  • Passengers – 283
  • Full Weight – 2003 tonnes
  • Kinetic Energy at 60 mph – 20.0 kWh

And these are for a Class 710 train.

  • Empty Weight – 157.8 tonnes
  • Passengers – 700
  • Full Weight – 220.8 tonnes
  • Kinetic Energy at 60 mph – 22.1 kWh

Note.

  1. The Aventra is twenty-seven tonnes lighter. But it doesn’t have a toilet and it does have simpler seating with no tables.
  2. The passenger weight is very significant.
  3. The full Aventra is heavier, due to the large number of passengers.
  4. There is very little difference in kinetic energy at a speed of 60 mph.

I have played with the model for some time and the most important factor in determining battery size is the energy consumption in terms of kWh per vehicle-mile. Important factors would include.

  • The aerodynamics of the nose of the train.
  • The turbulence generated by all the gubbins underneath the train and on the roof.
  • The energy requirements for train equipment like air-conditioing, lighting and doors.
  • The efficiency of the regenerative braking.

As an example of the improvement included in Aventras look at this picture of the roof of a Class 710 train.

This feature probably can’t be retrofitted, but I suspect many ideas from the Aventra can be applied to Electrostars to reduce their energy consumption.

I wouldn’t be surprised to see Bombardier push the energy consumption of an Electrostar with batteries towards the lower levels that must be possible with Aventras.

 

 

 

October 2, 2019 Posted by | Transport | , , , , , , , , , | Leave a comment

Bombardier And Hitachi Come Up With Similar Car Lengths

In an article in the October 2019 Edition of Modern Railways, which is entitled EMR Kicks Off New Era, more details of the new Hitachi bi-mode trains for East Midlands Railway are given.

This is said.

The first train is required to be available for testing in December 2021 with service entry between April and December 2022.

The EMR bi-modes will be able to run at 125 mph in diesel mode, matching Meridian performance in a step-up from the capabilities of the existing Class 80x units in service with other franchises. They will have 24 metre vehicles (rather than 26 metres), a slightly different nose to the ‘800s’ and ‘802s’, and will have four diesel engines rather than three.

I will examine this extract further.

Car Length

If you look at Bombardier’s Class 720 train, the five-car trains are 122 metres long, giving a 24 metre car length.

The ten car Class 720 train is 243 metres long, which is a similar length to three Class 360 trains running as a twelve-car train and only a few metres longer than three Class 321 trains running together.

This must be good for Greater Anglia’s train renewal, as it will minimise expensive platform lengthening.

It looks to me, that two of the new EMR InterCity trains running as a pair will be of a similar length to a twelve-car formation of Class 360 trains.

Consider.

  • As trains for EMR InterCity and EMR Electrics will share platforms at some stations, platform lengthening will again be minimised.
  • If you divide 240 by 10, you usually get the same answer of 24.
  • But if 26 metre cars were to be used, a nine-car EMR bi-mode would be 234 meres long. and two five-car trains working together would be 260 metres long.
  • Twelve-car Class 700 trains are 242.6 metres long.

These points lead me to believe that 24 metre cars are a better length for the Hitachi trains as ten-car formations are the same length as twelve-car formations of many of the UK’s older multiple units.

Maximum Speed On Diesel

Consider.

  • Various places on the Internet say that the maximum speed on diesel of a Class 800 train is 118 mph.
  • Maximum speed of a train is probably more determined by the aerodynamic drag of the train, which is proportional to the square of the speed.
  • So if a Class 800 train needs 3 * 560 kW to maintain 118 mph, it will need 1885 kW or 12.2 percent more power to maintain 125 mph
  • A fourth 560 kW diesel engine will add 33.3 percent more power.

This rough calculation shows that a fourth engine will allow the train to more than  attain and hold 125 mph on the same track where a Class 800 train can hold 118 mph.

But adding a fourth engine is a bit of a crude solution.

  • It will add more dead weight to the train.
  • It will be useful when accelerating the train, but probably not necessary.
  • It will add more noise under the train. Especially, if four cars had engines underneath.
  • It could cause overheating problems, which have been reported on the current trains.

I’ll return to this later.

Aerodynamics

Power required to maintain 125 mph can be reduced in another much more subtle way; by improving the aerodynamics.

  • I have stood on a platform, as an Aventra has silently passed at speed. It is very quiet, indicating that the aerodynamics are good.
  • But then Bombardier are an aerospace company as well as a train builder.

I’ve no idea if a Bombardier Class 720 train has less aerodynamic drag, than a Hitachi Class 800 train, but I’m sure that aerodynamic wizards from Formula One could improve the aerodynamics of the average modern train.

Could better aerodynamics explain why the EMR InterCity bi-modes are stated to have a different nose?

Look at the noses on these Spanish High Speed trains, which were built by Talgo!

Are they more aerodynamic? Do they exert a higher down-force making the train more stable?

They certainly are different and they obviously work., as these are very fast trains.

Incidentally, these trains, are nicknamed pato in Spanish, which means duck in English.

Aerodynamic drag is proportional to a drag coefficient for the object and the square of the speed.

Let’s assume the following.

  • The drag coefficient for the current train is d.
  • The drag coefficient for the train with the aerodynamic nose is a.
  • The terminal velocity of the train with the aerodynamic nose is v.

If the current Class 800 train travels at 118 mph on full power of 1680 kW, what speed would the train with an improved aerodynamic nose do on the same power, for various values of a?

If the new nose gives a five percent reduction in aerodynamic drag, then a = 0.95 * d, then the maximum speed of the train will be given by this formula

d * 118 * 118 = .0.95 * d * v* v

Solving this gives a speed of 121 mph.

Completing the table, I get the following.

  • A one percent reduction in drag gives 119 mph
  • A two percent reduction in drag gives 119 mph
  • A three percent reduction in drag gives 120 mph
  • A four percent reduction in drag gives 120 mph
  • A five percent reduction in drag gives 121 mph
  • A six percent reduction in drag gives 122 mph
  • A seven percent reduction in drag gives 122 mph
  • An eight percent reduction in drag gives 123 mph
  • A nine percent reduction in drag gives 124 mph
  • A ten percent reduction in drag gives 124 mph
  • An eleven percent reduction in drag gives 125 mph

I can certainly understand why Talgo have developed the duck-like nose.

The conclusion is that if you can achieve an eleven percent reduction in drag over the current train, then with the same installed power can raise the speed from 118 mph to 125 mph.

Why Have A Fourth Engine?

If aerodynamics can make a major contribution to the increase in speed under diesel, why add a fourth engine?

  • It might be better to fit four slightly smaller engines to obtain the same power.
  • It might be better to put a pair of engines under two cars, rather than a single engine under four cars, as pairs of engines might share ancillaries like cooling systems.
  • Extra power might be needed for acceleration.
  • Four engines gives a level of redundancy, if only three are needed to power the train.

I wouldn’t be surprised to find out, that Hitachi are having a major rethink in the traction department.

Will The Trains Have Regenerative Braking To Batteries?

I would be very surprised if they don’t, as it’s the only sensible way to do regenerative braking on diesel power.

Will The Trains Be Built Around An MTU Hybrid PowerPack?

This or something like it from Hitachi’s diesel engine supplier; MTU, is certainly a possibility and it would surely mean someone else is responsible for all the tricky software development.

It would give the following.

  • Regenersative braking to batteries.
  • Appropriate power.
  • Easier design and manufacture.
  • MTU would probably produce the sophisticated power control system for the train.
  • MTU could probably produce a twin-engined PowerPack

Rolls Royce MTU and Hitachi would all add to the perception of the train.

I would rate Hitachi using MTU Hybrid PowerPacks quite likely!

Would Two Pairs Of Engines Be Better?

The current formation of a five-car Class 800 train is as follows.

DPTS-MS-MS-MC-DPTF

Note.

  1. Both driver cars are trailers.
  2. The middle three cars all have generators, that are rated at 560 kW for a Class 800 train and 700 kW for a Class 802 train.
  3. Take a trip between Paddington and Oxford and you can feel the engines underneath the floor.
  4. The engines seem to be reasonably well insulated from the passenger cabin.

The system works, but could it be improved.

If I’m right about the aerodynamic gains that could be possible, then it may be possible to cruise at 125 mph using a power of somewhere around 1,800 kW or four diesel generators of 450 kW each.

Putting a diesel generator in four cars, would mean one of the driver cars would receive an engine, which might upset the balance of the train.

But putting say two diesel generators in car 2 and car 4 could have advantages.

  • A Class 800 train has a fuel capacity of 1,300 litres, which weighs 11.06 tonnes. and is held in three tanks. Would train dynamics be better with two larger tanks in car 2 and 4?
  • Could other ancillaries like cooling systems be shared between the two engines?
  • Could a substantial battery pack be placed underneath car 3, which now has no engine and no fuel tank?
  • As the engines are smaller will they be easier to isolate from the cabin?

The only problem would be fitting two generators underneath the shorter 24 metre car.

What size of battery could be fitted in car 3?

  • According to this datasheet on the MTU web site, the engine weighs between five and six tonnes.
  • I think this weight doesn’t  include the generator and the cooling systems.
  • Removing the fuel tank would save 3.7 tonnes

I suspect that a ten tonne battery could replace the diesel engine and its support systems in car 3..

On current battery energy densities that would be a battery of around 1000 kWh.

In How Much Power Is Needed To Run A Train At 125 mph?, I estimates that an electric  Class 801 train needs 3.42 kWh per vehicle mile to maintain 125 mph.

This would give a range of almost sixty miles on battery power.

The battery would also enable.

  • Regenerative braking to batteries, which saves energy at station stops.
  • Diesel engines would not need to be run in stations or sensitive areas.
  • Battery power could be used to boost acceleration and save diesel fuel.

You can almost think of the battery as an auxiliary engine powered by electrification and regenerative braking, that can also be topped up from the diesel generators.

It should also be noted, that by the time these trains enter service, the Midland Main Line will be electrified as far as Kettering and possibly Market Harborough.

This will enable the following.

  • Trains will leave the electrification going North with a full battery.
  • As Nottingham is less than sixty miles from Kettering and the trains will certainly have regeneratinve braking, I would not be surprised to see Northbound services to Nottingham being almost zero-carbon.
  • A charging station at Nottingham would enable Southbound services to reach the electrification, thus making these services almost zero-carbon.
  • Trains would be able to travel between Derby and Chesterfield, which is only 23 miles, through the World Heritage Site of the Derwent Valley Mills, on battery power.
  • Corby and Melton Mowbray are just 26 miles apart, so the bi-mode trains could run a zero-carbon service to Oakham and Melton Mowbray.
  • Trains could also run between Corby and Leicester on battery power.
  • If and when the Northern end of the route is electrified between Sheffield and Clay Cross Junction ion conjunction with High Speed Two, the electrification gap between Clay Cross Junction and Market Harborough will be under seventy miles, so the trains should be able to be almost zero carbon between London and Sheffield.

It does appear that if a battery the same weight as a diesel generator, fuel tank and ancillaries is placed in the middle car, the services on the Midland Main Line will be substantially zero-carbon.

What Would Be The Size Of |The Diesel Engines?

If the battery can be considered like a fifth auxiliary engine, I would suspect that the engines could be much smaller than the 560 kWh units in a Class 800 train.

Improved aerodynamics would also reduce the power needed to maintain 125 mph.

There would also be other advantages to having smaller engines.

  • There would be less weight to accelerate and lug around.
  • The noise from smaller engines would be easier to insulate from passengers.
  • Engines could be used selectively according to the train load.
  • Engines might be less prone to overheating.

The mathematics and economics will decide the actual size of the four engines.

Earlier, I estimated that a 10-11 % decrease in the trains aerodynamic drag could enable 124-5 mph with 1680 kW.

So if this power was provided by four engines instead of three, they would be 420 kW engines.

Conclusion

The Hitachi bi-modes for East Midlands Railway will be very different trains, to their current Class 80x trains.

September 26, 2019 Posted by | Transport | , , , , , , , | Leave a comment