The Anonymous Widower

Do Aventras Use Supercapacitors?

In this article in Global Rail News from 2011, which is entitled Bombardier’s AVENTRA – A new era in train performance, gives some details of the Aventra’s electrical systems. This is said.

AVENTRA can run on both 25kV AC and 750V DC power – the high-efficiency transformers being another area where a heavier component was chosen because, in the long term, it’s cheaper to run. Pairs of cars will run off a common power bus with a converter on one car powering both. The other car can be fitted with power storage devices such as super-capacitors or Lithium-ion batteries if required. The intention is that every car will be powered although trailer cars will be available.

Unlike today’s commuter trains, AVENTRA will also shut down fully at night. It will be ‘woken up’ by remote control before the driver arrives for the first shift

This was published over seven years ago, so I suspect Bombardier have refined the concept.

The extract makes three interesting points.

All Or Most Cars Will Be Powered

In A Detailed Layout Drawing For A Class 345 Train, I give the formation of a Crossrail Class 345 train.

DMS+PMS+MS1+MS3+TS(W)+MS3+MS2+PMS+DMS

Note.

  1. M signifies a motored car.
  2. Eight cars have motors and only one doesn’t.
  3. The train is composed of two identical half-trains, which are separated by the TS(W) car.
  4. There are four wheelchair spaces in the TS(W) car.

Are the MS!, MS2 and MS3 cars identical?

In addition, I have been told, that all cars in Class 720 trains are motored.

It does seem that Bombardier have fulfilled their statement from 2011.

Remote Wake-Up

This is mentioned in the extract, but there are few other references to it. I quoted a report from the Derby Telegraph, which has since been deleted, in Do Bombardier Aventras Have Remote Wake-Up?.

Supercapacitors And Lithium-Ion Batteries

According to the extract, the trains have been designed to accept supercapacitors or lithium-ion batteries if required.

As the other two statements in the extract appear to be likely, I will continue to believe that all Aventras can have some form of energy storage.

Crossrail

I’ll look first at Crossrail’s Class 345 train.

In How Much Energy Does A Crossrail Class 345 Train Use?, using the train’s data sheet, I came to the conclusion, that electricity usage of the trains is 2.67 KWh per car per kiometre or 3.29 KWh per car per mile.

In the linked post, I also calculate the kinetic energy of a fully-loaded nine-car Crossrail train.

I’ll repeat it.

  • If I take a nine-car Class 345 train, this has a mass of less than 350 tonnes and a maximum speed of 145 kph.
  • 1500 passengers at 80 kg each works out at another 120 tonnes.
  • So for this crude estimate I’ll use 450 tonnes for the mass of a loaded train.

This gives the train a kinetic energy of 101 KWh.

As the Class 345 trains are effectively two half trains, with two PMS cars with pantographs, it is likely that they have at least two cars that are ready for supercapacitors or lithium-ion batteries.

The Design Of Crossrail

Crossrail could best be described as the Victoria Line on steroids.

  • Both lines were designed to run in excess of twenty-four trains per hour (tph) across London.
  • The Victoria Line was built to deep-level Underground standards, with one of the most advanced-for-its-time and successful train operating systems of all times.
  • Crossrail is a modern rail line being built to National Rail standards, with world-leading advanced technology, that takes full account of modern environmental standards and aspirations.

Costs were saved on the Victoria Line by leaving out important parts of the original design..

Costs were saved on Crossrail, by using high-quality design.

  • Crossrail and the Great Western Main Line electrification share a sub-station to connect to the National Grid.
  • The number of ventilation and access shafts was reduced significantly, with one in a new office block; Moor House.
  • Electrification uses a simple overhead rail, which is only fed with power at the ends.

I also believe that the Class 345 trains, which were designed specifically for the route, were designed to save energy and increase safety in the tunnels.

Regenerative braking normally saves energy by returning braking energy through the electrification, so it can be used to power other nearby trains.

Batteries For Regenerative Braking

However, in recent years, there has been increasing interest in diverting the braking energy to onboard energy storage devices on the train, so that it can be used when the train accelerates or to power systems on the train.

The system has these advantages.

  • Less energy is needed to power the trains.
  • Simpler and less costly transformers  can be used for the electrification.
  • The onboard energy storage can be used to power the train after an electrification failure.
  • In tunnels, there is less heat-producing electricity flowing in all the cables.

Obviously, keeping the heat down in the tunnels is a good thing.

A Station Stop On Crossrail Using Regenerative Braking And Energy Storage

Imagine a fully-loaded train approaching a station, at the maximum speed on 145 kph.

  • The train will have a kinetic energy of 101 kWh.
  • As it approaches the station, the brakes will be applied and the regenerative brakes will turn the train’s energy into electricity.
  • This energy will be stored in the onboard energy storage.
  • As the train accelerates away from the station, the electricity in the onboard energy storage can be used.

The only problem, is that regenerative braking is unlikely to recover all of the train’s kinetic energy. But this is not a big problem, as the train draws any extra power needed from the electrification.

To make the system as efficient as possible, the following must be fitted.

  1. The most efficient traction motor.
  2. Onboard energy storage capable of handling the maximum kinetic energy of the train.
  3. Onboard energy storage with a fast response time.

The train will probably be controlled by a sophisticated computer system.

What Size Of Onboard Energy Storage Should Be Fitted?

Obviously, this is only speculation and a best guess, but the following conditions must be met.

  • The onboard energy storage must be able to capture the maximum amount of energy generated by braking.
  • The physical size of the energy storage system must be practical and easily fitted under or on the train.
  • The energy storage system should be able to store enough energy to be able to move a stalled train to safety in the event of complete power failure.

Note that an energy storage system with a 100 kWh capacity would probably take the train somewhere around four to five kilometres.

Obviously, a series of computer simulations based on the route, passengers and various other conditions, would indicate the capacity, but I feel a capacity of around 120 kWh might be the place to start.

Where Would The Energy Storage Be Placed?

With nine cars, and with eight of them motored, there are a several choices.

  • One energy storage unit in all motored cars.
  • One energy storage unit in the three MS cars.
  • One energy storage unit in each half train.

I’ve always liked the concept of an energy storage unit in each powered car, as it creates a nice tight unit, with energy stored near to where it is generated and used.

But there is another big advantage in splitting up the energy storage – the individual units are smaller.

Could this mean that supercapacitors could be used?

  • The main need for onboard energy storage is to handle regenerative braking.
  • The secondary need for onboard energy storage is for emergency power.
  • There is no needon Crossrail as yet,to run the trains for long distances on stored power.
  • Supercapacitors are smaller.
  • Supercapacitors can handle more operating cycles.
  • Supercapacitors run cooler.
  • Supercapacitors have a fast response.

If running for longer distances were to be required in the future, which might require lithium-ion or some other form of batteries, I’m sure there will be space for them, under all those cars.

I wouldn’t be surprised to find out that Crossrail’s Class 345 trains are fitted with supercapacitors.

Note, that  a Bombardier driver-trainer, talked of an emergency power supply, when I asked what happens if the Russians hacked the electrification.

Class 710 Trains

London Overground’s Class 710 trains are a bit of a mystery at the moment as except for a capacity of seven hundred passengers disclosed in this article on the International Railway Journal little has been published.

Here are my best guesses.

Formation

Based on the formation of the Class 345 trains, I think it will be.

DMS+PMS+MS+DMS

Effectively, this is a half-train of a seven-car Class 345 train, with a DMS car on the other end.

Dimensions

I have a Bombardier press release, which says that the car length is twenty metres, which is the same as Class 315, Class 317 and Class 378 trains and a whole load of other trains, as twenty metre cars, were a British Rail standard.

I doubt there will be much platform lengthening for these trains in the next few years.

Weight

The Wikipedia entry for Aventra gives car weight at between thirty and thirty-five tonnes, so the train weight can be anything between 120-140 tonnes.

Passenger Capacity

I wrote about this in The Capacity Of London Overground’s New Class 710 Trains.

This was my conclusion.

It appears that seven hundred is the only published figure and if it is, these new Class 710 trains are going to substantially increase public transport capacity across North London.

They are certainly future-proofed for an outbreak of London Overground Syndrome, where passenger numbers greatly exceed forecasts.

As some of the trains are being delivered as five-car units, there is always the option of adding an extra car. Especially, as the platforms on the line, seem to have been built for five or even six car trains.

London Overground have not made the platform length miscalculations of the North and East London Lines.

For the near future they’ll hold around 700 passengers at 80 Kg. each, which means a passenger weight of fifty-six tonnes.

Full Train Weight

For various train weights, the fully-loaded trains will be.

  • 120 tonnes – 176 tonnes
  • 130 tonnes – 186 tonnes
  • 140 tonnes – 196 tonnes

Until I get a better weight for the train, I think I’ll use 130 tonnes or 186 tonnes, when fully-loaded.

Speed

I wrote about this in What Is The Operating Speed Of Class 710 Trains?.

This was my conclusion.

But what will be the operating speed of the Class 710 trains?

I said it will be somewhere between 145 kph (90 mph) and 160 kph (100 mph)

Consider.

  • I think that 145 kph, will be able to handle the two planned increased frequencies of four tph.
  • 145 kph is identical to the Crossrail trains.
  • 160 kph is identical to the Greater Anglia trains.
  • 160 kph seems to be the speed of suburban Aventras.

It’s a difficult one to call!

I do think though, that trundling around the Overground, they’ll be running at the same 121 kph of all the other trains.

Kinetic Energy

The kinetic energy of a 186 tonnes train at 121 kph is 29 kWh.

Could Supercapacitors Handle This Amount Of Energy?

I’m pretty certain they could.

Conclusion

Supercapacitors are a possibility for both trains!

I’ll review these calculations, as more information is published.

 

November 11, 2018 Posted by | Travel | , , , , , | Leave a comment

Thoughts On A Battery/Electric Train With Batteries And Capacitors

I’m going to use a Class 350/2 train as the example.

In Porterbrook Makes Case For Battery/Electric Bi-Mode Conversion, I calculated the kinetic energy of one of these trains at various speeds.

Wikipedia gives this information.

  • Maximum Speed – 100 mph
  • Train Weight – 175.5 tonnes
  • Capacity – Around 380 passengers

If I assume each passenger weighs 90 Kg with baggage, bikes and buggies, the train weight is 209.7 tonnes.

This weight could be a bit high, bnut then the train must perform even when crush-loaded.

Using Omni’s Kinetic Energy Calculator, I get the following kinetic energies at various speeds.

  • 80 mph – 37.2 kWh
  • 90 mph – 47.1 kWh
  • 100 mph – 58.2 kWh
  • 110 mph – 70.4 kWh

In the video shown in A Must-Watch Video About Skeleton Technologies And Ultracapacitors., Taavi Madiberk of Skeleton Technologies likens a capacitor/battery energy store with Usain Bolt paired with a marathon runner. Usain would handle the fast energy transfer of braking and acceleration, with the marathon runner doing the cruising.

This would seem to be a good plan, as the capacitors  could probably quickly store the regenerative braking energy and release it at a high rate to accelerate the train.

Once, up to operating speed, the lithium-ion batteries would take over and keep the train at the required speed.

Obviously, it would be more complicated than that and the sophisticated control system would move electricity about to keep the train running efficiently and to maximum range.

The capacitors should probably be sized to handle all the regenerative braking energy, so for a 100  mph train, which would have a kinetic energy of 58.2 kWh, a 100 kWh capacitor would probably be large enough.

In some ways the lithium-ion batteries can be considered to be a backup to the capacitors.

  • They provide extra power where needed.
  • If during deceleration, the capacitors become full, energy could be transferred to the lithium-ion batteries.
  • If after acceleration, the capacitors have got more energy than they need, it could be transferred to the lithium-ion batteries.
  • The lithium-ion batteries would probably power all the hotel services, like air-con, lights doors etc.  of the train.

Note that the energy transfer between the capacitors and the lithium-ion batteries should be very fast.

A good Control Engineer could have a lot of fun with sorting the trains control system.

 

 

 

November 11, 2018 Posted by | Travel | , , , | Leave a comment

A Must-Watch Video About Skeleton Technologies And Ultracapacitors

This video is embedded in this page on the Skeleton Technologies web site.

Watch it!

A few points,

  • Batteries have typically a life of between 3,000 to 5,000 cycles.
  • Capacitors can achieve up to a million cycles.
  • Used together batteries and capacitors complement each other.
  • Used together can double battery life.

Taavi Madiberk of Skeleton Technologies likens a capacitor/battery energy store with Usain Bolt paired with a marathon runner. Usain would handle the fast energy transfer of braking and acceleration, with the marathon runner doing the cruising.

Ultracapacitors For The Rail Industry

The title of this sub-section is the same as this page on the Skeleton Technologies web site.

Noted applications include.

  • Engine starting for diesel trains.
  • Kinetic Energy Recovery System (KERS) for diesel trains.
  • Onboard application for electric trains
  • Stationary application for rail industry
  • Independent power for level crossings.

I suspect these applications are just the start.

Conclusion

It appears to me, that the development of these large supercapacitors, is going to open up opportunities to develop energy storage systems for transport applications, that will give longer range and aincreased energy efficiency.

 

November 9, 2018 Posted by | Travel | , , | 2 Comments

Wright Bus Embraces Ultracapacitors

This press release from Skeleton Technologies is entitled Graphene-Based Ultracapacitors Boost Double and Single Decker-Buses Through Low Emission Zones by Reducing Fuel Consumption.

This is said.

The integration of graphene-based ultracapacitors into test WrightBus double deck buses enables a 36% fuel saving compared to a UK based EuroVI diesel bus baseline. It also adds at least another 3 passengers to the capacity of these buses compared to a lithium battery-based hybrid equivalent.

I have a feeling that graphene-based ultracapacitors will give lithium batteries a very good kicking.

 

 

 

 

November 8, 2018 Posted by | Travel | , , , | Leave a comment

Charging Battery/Electric Trains En-Route

One big need with a battery/electric hybrid train, is the need to charge the batteries quickly at a station stop.

On my last trip to Sheffield, I timed the stops from brakes on to moving again of the Class 222 train.

Times in minutes:seconds were as follows.

  • Leicester 1:30
  • Louthborough 1:15
  • East Midlands Parkway 1:06
  • Long Eaton 1:08
  • Derby 1:22
  • Chesterfield 1:09

So it looks like there is only a minute to charge the batteries on a typical Inter-City service.

Would it be much longer on say a long rural service like Settle and Carlisle or Inverness to Wick?

I don’t think so!

So how could we top up the train in a station stop of less than a minute.

Plug The Train Into a Power Socket

This may work with electric cars, but if you think it would work with trains and charge them in a minute, then think again!

Using A Pantograph

This may seem to be the obvious way, but to raise the pantograph, get a reasonable charge into the train’s batteries and lower it again, is an awful lot of things to cram into a minute.

There’s also many things that can go wrong.

Vivarail’s Solution

In Issue 864 of Rail Magazine, there is an article entitled Scotland High Among Vivarail’s Targets for Class 230 D-Trains, Vivarail’s solution to charging a battery-powered Class 230 train is disclosed.

A prototype rapid charging facility at its Long Marston base would use short sections of third-rail to quickly recharge a Class 230’s batteries. He said that the third-rail shoegear fitted to the trains in their London Underground service could handle higher currents than simply plugging a cable into the train.

The rapid charging concept consists of a shipping container of batteries that are trickle charged from a mains supply. When a Class 230 sits over the short sections of third-rail, electricity can be quickly transferred to the train’s batteries. When the train is away, the power rails are earthed to ensure they pose no risk The concept provides for charging a Class 230 as it pauses at a terminus before making its return journey.

What surprises me, is the claim, that third-rail is such an effective way of charging the batteries.

But then a Class 92 locomotive has a power of 4,000 kW when running on 750 VDC third rail electrification, so it would appear third-rail systems can handle large amounts of power.

This would be the sequence, as a train performed a station stop.

  1. The driver would stop the train at the defined place in the platform, as thousands of train drivers do all over the world, millions of times every day.
  2. Once stopped, the contact shoes on the train would be in contact with the third rail, as they would be permanently down and ready to accept electricity at all times.
  3. The charging system would detect the stationary train and that the train was connected, and switch on the power supply. to the third-rail.
  4. Electricity would flow from the track to the batteries, just as if the train was on a standard third-rail electrified track.
  5. If the train’s battery should become full, the train’s system could stop the charging.
  6. When passengers had finished leaving and joining the train and it was safe to do so, the driver would start the train and drive it to the next station, after ascertaining, that there was enough power in the batteries.
  7. When the charging system determined that the train was moving or that the contact shoe was no longer connected to the third-rail, it would immediately cut the power to the rail and connect it to earth.

It is a brilliant system; simple, efficient and fail-safe.

  • Regenerative braking will mean that stopping in the station will help to top-up the batteries.
  • The battery on the train is being charged, as long as it is stationary in the station.
  • Delays in the station have no effect on the charging, except to allow it for longer if the battery can accept more charge.
  • The driver concentrates on driving the train and doesn’t have to do anything to start and stop the charging.
  • As there is no cable to disconnect or pantograph to lower, disconnection from the charging system is automatic and absolute, when the train leaves.
  • The charging system never exposes a live rail to passengers and staff.

As a Control and Electrical Engineer, I believe that developments of this system, could be able to put at least 200 kWh into the train’s batteries at each stop.

The system could also be independent of the driver, whose only actions would be to check on safety, that charging was proceeding as it should and that there was sufficient charge in the batteries before continuing.

Connection And Disconnection To The Third-Rail

These pictures taken at Blackfriars station, show how the ends of the third-rail is tapered, so that the shoe on the train connects and disconnects smoothly.

Note.

  1. The tapered ends of both rails on opposite side of the gaps.
  2. For safety, the electrified third-rail is on the other side of the track to the platform.
  3. One picture shows how yellow-painted wood is used for extra safety.

As a train is always on top of the third-rail, when the power to the rail is switched on in Vivarail’s charging system, I think that, the system should be very safe.

Battery-To-Battery Energy Transfer

Vivarail’s genius is to transfer the energy from trackside batteries to the batteries on the train. As batteries have a low impedance, large amounts of electricity can be passed quickly.

Batteries, Supercapacitors Or Both?

I believe that in a few years time for many applications, supercapacitors  will be a viable alternative to batteries.

Energy densities are improving in supercapacitors and they have a similar low impedance, which will enable fast transfer of electricity.

So I wouldn’t be surprised to supercapacitors used on trains or in charging systems.

It may be that a mix of supercapacitors and batteries is the optimal solution.

Installing A Vivarail-Style Charging System

Installation of a Vivarail-style charging system would require.

  • A length of third rail to be installed alongside the track or tracks in the station.
  • The containerised batteries and control system to be installed in a suitable place.
  • Electrical power to be connected to the batteries and control system.
  • Appropriate-cabling between the rail and the container.

The great advantage is that to install a charging system in a station would not require any of the complicated and expensive works, often needed to install 25 KVAC overhead electrification.

Supplying Electricity To A Vivarail-Style Charging System

The Rail Magazine article talks of trickle charging the track-side batteries, using mains electricity, but I suspect some of the most cost-effective systems would use solar, wind or water power, backed up by a mains supply.

In a remote station, installing a Vivarail-style charging system powered by a sustainable power might be an opportunity to install modern low-energy lights and other equipment at the station, powered from the charging system.

A Vivarail-Style Charging System Could Be Built With No Visual Intrusion

Another advantage of using Vivarail-style charging systems, is that there is less visual intrusion than traditional continuous 25 KVAC overhead electrification.

Some visual intrusion would be down to the shipping container used to house the batteries.

But if necessary, the batteries could be housed in a classic Victorian outhouse or a modern sympathetically-designed structure.

Would A Vivarail-Style Charging System Need To Be In A Station?

Many, but not all charging systems would be in stations.

However, there are some very convenient places for charging systems, that may not be in stations.

Trains going to Bedwyn station wait for several minutes  in a turnback siding to the West of the station, before returning to London. The route is not electrified and bi-mode Class 800 trains will be used on the route, because there is about thirteen miles between Bedwyn and Newbury without electrification.

If a Vivarail-style charging system were to be added to the turnback siding battery/electric trains could work the service to London. I’m sure Hitachi know how to convert a version of a Class 80x train to battery/electric operation.

There will be quite a few places, where for operational reasons, a charging system could or should be placed.

Would All Stations On A Route Need To Be fitted With A Vivarail-Style Charging System?

This would depend on the route and the need to run it reliably.

Detailed computer modelling would show, which stations wouldn’t need to be fitted with charging systems!

If a train was a limited-stop service or not required to stop at a particular station because of operational reasons or the timetable, the train would just pass through the station.

As it didn’t stop, it would not have caused the charging system to switch on power to the third-rail.

But if say due to delays caused by an incident meant a train was low on battery power, there is no reason, why the train can’t make a stop at any charging system to top-up the batteries.

Should The Driver Have Any Control?

Consider.

  • It may be extra safety is needed, so the driver could  give a signal to the charging system, that it is safe to start the charging process.
  • Similarly, the driver should be able to pause or stop the process at any time.

But the driver would mainly be monitoring an automatic process.

Would The Charging System Be Linked To The Signalling?

I think this could be likely, as this could add another level of safety.

Conclusion

I believe it is possible to design a safe charging system using proven third-rail technology and batteries or supercapacitors to transfer at least 200 kWh into a train’s batteries at each stop.

Surely, this method of electrification could be used to allow electric trains to run through environmentally-sensitive areas and World Heritage sites like Bath, the Lake District and the Forth Bridge,

November 2, 2018 Posted by | Travel | , , , , | 5 Comments

Brush Traction Signs Contract With Skeleton Technologies For Modules For Class 769 Trains

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

This is the first two paragraphs

Skeleton Technologies has announced that they have signed a contract with Brush Traction to supply SkelStart Engine Start Modules for all Porterbrook Bi Mode Class 769 trains.

The high-power density, safe and tiny size of the 24V SkelStart module were decided over other solutions during the feasibility stage to start the Auxiliary Power Supply (APS) units. Simply put, there was not enough room available for another solution.

The article then gives a few brief details on the SkelStart

Who are Skeleton Technologies?

They have a web site at www.skeletontech.com and there is a brief description on the home page.

Under a title of.

Powering Energy Savings With Ultracapacitors

There is this description.

Skeleton Technologies’ patented curved graphene is changing the world of energy storage. 

Our superior technology enables us to deliver ground-breaking energy storage solutions with market leading power and energy density. Our products are used across industries from automotive to aerospace and everything in between.

Curved graphene? I know about graphene, but I’d never heard of it being curved.

There is a Press Release on the Skeleton Technologies web site, which is entitled Skeleton Technologies Signs Contract with Brush Traction to Supply Ultracapacitors for All BMU Class 769 Prime Movers.

This gives a lot more details, including this brief description of size and weight.

The 24V SkelStart has the size of a regular car battery and with its 8kg weight, it solved the space restriction we had.

It looks to be a very simple application of a capacitor with the ability to hold a lot of charge.

One of their products is called a SkelMod 170V 53F Ultracapacitor Module.

The datasheet gives these details.

  • Voltage – 170 Volts
  • Capacitance – 53 Farads
  • Maximum Stored Energy – 0.2127 kWh
  • Weight – 77 Kg.

That is a lot of energy for a capacitor.

A 50 kWh capacitor suitable for a bus or train, with this energy density would weigh eighteen tonnes, so it’s a bit impractical for this type of application at present.

But who knows what will be possible in the near future?

Skeleton Technologies would already appear to have pushed capacitor design a long way.

Skeleton Technologies Are An Estonian Company

This surprised me at first! But why not?

An Aside

Somewhere in my past about the 1960s, I remember an electronic news item, where someone like AERE Harwell, had built a one Farad capacitor, that was house-sized. Noe we get 53 Farad in a suitcase.

Conclusion

I think we’ll eventually see supercapacitors big enough to replace lithium-ion batteries in a lot of applications.

September 20, 2018 Posted by | Travel, World | , , , | 2 Comments