The Anonymous Widower

Batteries On Class 777 Trains

In this article on Railway Gazette, which is entitled Merseyrail Class 777 arrives in Liverpool, there is this sentence.

There is space under one vehicle to house a battery weighing up to 5 tonnes within the axleload limit.

This matter-of-fact sentence, draws me to the conclusion, that these trains have been designed from the start to allow future battery operation.

Batteries are not an add-on squeezed into a design with great difficulty.

Battery Capacity

Energy densities of 60 Wh/Kg or 135 Wh/litre are claimed by Swiss battery manufacturer; Leclanche.

This means that a five tonne battery would hold 300 kWh.

Note that Vivarail find space for 424 kWh in the two-car Class 230 train, I wrote about in Battery Class 230 Train Demonstration At Bo’ness And Kinneil Railway, so it would appear that Stadler aren’t being over ambitious.

Kinetic Energy Of A Full Class 777 Train

The weight of a full Class 777 train is calculated as follows.

  • Basic empty weight – 99 tonnes
  • Battery weight – 5 tonnes
  • 484 passengers at 80 Kg – 38.72 tonnes

Which gives a total weight of 143.72 tonnes.

Intriguingly, the weight of a current Class 507 train is 104.5 tonnes, which is 500 Kg more than an empty Class 777 train with a battery!

If these weights are correct, I suspect Stadler have used some very clever lightweight design techniques.

For various speeds, using Omni’s Kinetic Energy Calculator, this weight gives.

  • 30 mph – 3.6 kWh
  • 40 mph – 6.4 kWh
  • 50 mph – 10.0 kWh
  • 60 mph – 14.4 kWh
  • 70 mph – 19.5 kWh
  • 75 mph – 22.4 kWh

Note.

  1. The average speed between Bidston and Wrexham General stations on the Borderlands Line is under 30 mph
  2. The operating speed on the Wirral Line is 70 mph
  3. The operating speed on the Northern Line is 60 mph
  4. The maximum speed of the trains is 75 mph.

Every time I do these calculations, I’m surprised at how low the kinetic energy of a train seems to be.

How Small Is A Small Battery?

One battery doesn’t seem enough, for a train designed with all the ingenuity of a product with quality and precision, that is designed to out-perform all other trains.

This is another paragraph from the Railway Gazette article.

According to Merseytravel, ‘we want to be able to prove the concept that we could run beyond the third rail’. By storing recovered braking energy, the batteries would help to reduce power demand and the resulting greenhouse gas emissions. All of the Class 777s will be fitted with small batteries to allow independent movement around workshop and maintenance facilities.

I am not quite sure what this means.

It would seem strange to have two independent battery systems in one train.

I think it is more likely, that the smaller battery can be considered the primary battery of the train.

  • After all in the depot, it looks after the train’s power requirement.
  • Does it also handle all the regenerative braking energy?
  • Is it used as a secondary power supply, if say the power is low from the electrification?
  • Could it be used to move the train to the next station for passenger evacuation in the event of a power failure?

I wonder if the power system is a bit like the average battery-powered device like a lap-top computer, smart phone or hybrid car.

  • The electrification and the regenerative braking charges the battery.
  • The battery provides the traction and hotel power for the train.

When the five tonne battery is fitted, does the train’s control system move power between the two batteries to drive the train in the most efficient manner?

I’ll return to factors that define the size of the small battery.

The small battery must be big enough for these purposes.

  • Handling regenerative braking at the operating speed.
  • Recovering a full train to the next station.
  • Keeping a train’s systems running, during power supply problems.
  • Moving a train around a depot

As the lines leading to depots are electrified, the train can probably enter a depot with a battery fairly well-charged.

As the new Class 777 trains have a maximum operating speed of 75 mph, I would suspect that the small battery must be able to handle the regenerative braking from 75 mph, which my calculations show is 22.4 kWh with a full train. Let’s call it 30 kWh to have a reserve.

Using Leclanche’s figures, a 30 kWh battery would weigh 500 Kg and have a volume of just under a quarter of a cubic metre (0.222 cubic metre to be exact!)

I suspect the operation of the small battery through a station would be something like this.

  • As the train runs from the previous station, the power from the battery will be used by the train, to make sure that there is enough spare capacity in the battery to accommodate the predicted amount of energy generated by regenerative braking.
  • Under braking, the regenerative braking energy will be stored in the battery.
  • Not all of the kinetic energy of the train will be regenerated, as the process is typically around eighty percent efficient.
  • Whilst in the station, the train’s hotel services like air-conditioning, lights and doors, will be run by either the electrification if available or the battery.
  • When the train accelerates away, the train’s computer will use the optimal energy source.

The process will repeat, with the battery constantly being charged under braking and discharged under acceleration.

Lithium-ion batteries don’t like this cycling, so I wouldn’t be surprised to see dome other battery or even supercapacitors.

A Trip Between Liverpool and Wrexham Central in A Class 777 Train With A Battery

The train will arrive at Bidston station with 300 kWh in the battery, that has been charged on the loop line under the city.

I will assume that the train is cruising at 50 mph between the twelve stops along the twenty-seven and a half miles to Wrexham Central station.

At each of the twelve stops, the train will use regenerative braking, but it will lose perhaps twenty percent of the kinetic energy. This will be two kWh per stop or 24 kWh in total.

I usually assume that energy usage for hotel functions on the train are calculated using a figure of around three kWh per vehicle mile.

This gives an energy usage of 330 kWh.

But the Class 777 trains have been designed to be very electrically efficient and the train is equivalent in length to a three-car Class 507 train.

So perhaps a the calculation should assume three vehicles not four.

Various usage figures give.

  • 3 kWh per vehicle-mile – 247.5 kWh
  • 2.5 kWh per vehicle-mile – 206 kWh
  • 2 kWh per vehicle-mile – 165 kWh
  • 1.5 kWh per vehicle-mile – 123.8 kWh
  • 1 kWh per vehicle-mile – 82.5 kWh

Given that station losses between Bidston and Wrexham Central could be around 24 kWh, it looks like the following could be possible.

  1. With a consumption of 3 kWh per vehicle-mile, a Class 777 train could handle the route, but would need a charging station at Wrexham Central.
  2. If energy consumption on the train could be cut to 1.5 kWh per vehicle-mile, then a round trip would be possible.

It should also be noted that trains seem to do a very quick stop at Wrexham Central station of just a couple of minutes.

So if charging were to be introduced, there would need to be a longer stop of perhaps eight to ten minutes.

But the mathematics are telling me the following.

  • The Class 777 train has been designed to weigh the same empty as a current Class 507 train, despite carrying a five tonne battery.
  • If power consumption can be kept low, a Class 777 train with a battery can perform a round trip from Liverpool to Wrexham Central, without charging except on the electrified section of line between Liverpool and Bidston.
  • Extra stops would probably be possible, as each would consume about 2 kWh

I feel that these trains have been designed around Liverpool to Wrexham Central.

Conclusion

Wrexham Central here we come!

Other routes are possible.

  • Hunts Cross and Manchester Oxford Road – 27 miles
  • Ormskirk and Preston – 15 miles
  • Headbolt Lane and Skelmersdale – 6 miles
  • Ellesmere Port and Helsby – 5 miles
  • Kirkby and Wigan Wallgate – 12 miles

Chargers will not be needed at the far terminals.

February 4, 2020 Posted by | Transport/Travel | , , , , , , , , | 18 Comments

Could Modern Energy Systems Have A Secondary Role?

Close to where I live is a small heat and power system, that I wrote about in The Bunhill Energy Centre.

I first went over the centre during Open House.

Several of these modern systems are very good demonstrations of the principles of maths, physics and engineering.

So do these innovative energy systems do their bit in educating the next generation of scientists and engineers?

Some of the modern systems, that are in development like Highview Power’s energy storage using liquid air would be ideal for a secondary education role!

Most too, are very safe, as there are no dangerous processes or substances.

And in the next few years, there will be more systems all over the country and many in the hearts of towns and cities. Some schools, colleges and especially universities, will have their own innovative energy sources.

Liverpool University already has a system, which is described here.

January 16, 2020 Posted by | Energy Storage | , , , , , , | Leave a comment

The Mathematics Of Fast-Charging Battery Trains Using Third-Rail Electrification

In Vivarail Unveils Fast Charging System For Class 230 Battery Trains, I talked about how Vivarail are proposing to fast-charge their Class 230 trains.

  • The trains are fitted with special high-capacity third rail shoes.
  • Third-rail electrification is laid in stations.
  • The third rail is powered by a bank of bstteries, that are trickle-charged from the mains or perhaps even solar power.
  • When the train connects to the rail, the rail is made live and a fast transfer takes place between third-rail and train.

So how much electricity could be passed to a train during a stop?

The most powerful locomotive in the UK, that can use 750 VDC third-rail electrification is a Class 92 locomotive.

According to Wikipedia, it can produce a power output of 4 MW or 4,000 kW, when working on third-rail electrification.

This means, that in an hour, four thousand kWh will be transferred to the train using conventional third-rail electrification.

Or in a minute 66.7 kWh can be transferred.

In Vivarail’s system, because they are transferring energy between batteries, enormous currents can be passed.

To illustrate how batteries can can deliver enormous currents here’s a video of  a guy using two car batteries to weld things together.

These currents are possible because batteries have a low impedance and when the battery on the train is connected to the battery bank on the station, the two batteries will equalise their power.

If we take the example of the Class 92 locomotive and conventional electrification, this would be able to transfer 200 kWh in three minutes or 400 kWh in six minutes.

But I believe that battery-to-battery transfers could be at a much higher current

Thus in a typical one or two minute stop in a station, upwards of 200 kWh could be transferred to the train.

On this page of their web-site, Vivarail say this.

Due to the high currents required for the train Vivarail uses a carbon ceramic shoe able to withstand the heat generated in the process – without this shoe the charge time would make operational running unfeasible.

The devil is always in the details! From what I’ve seen and heard about the company, that would fit!

 

July 12, 2019 Posted by | Energy, Transport/Travel | , , , , , , | 6 Comments

Mathematics Of A Stadler Flirt Akku Battery Train

In Stadler Receives First Flirt Akku Battery Train Order, I  quoted this from as that of this article in Railway Gazette International.

Schleswig-Holstein transport authority NAH.SH has selected Stadler to supply 55 Flirt Akku battery multiple-units to operate regional services and provide 30 years of maintenance.

This is a substantial order for a large number of trains and many years of maintenance, and would appear to be structured similarly to deals in East Anglia, Glasgow and Liverpool in the UK.

Does The Train Have A Central Power-Pack Car?

Is the Flirt Akku, similar to Greater Anglia’s Class 755 trains and other of the companies products, in that it has a central power-pack car?

This picture shows a Class 755 train at Norwich.

 

Note that this four-car train has four full-size cars and a shorter one, that doesn’t appear to have any doors or proper windows.

This is the power-pack car, which in these trains has the following properties.

  • The power-pack car is 6.69 metres long.
  • The power-pack car is identical in both the four-car and three-car versions of the Class 755 trains.
  • The four-car trains have four diesel engines.
  • The three-car trains have two diesel engines.

The number of engines possible, leads me to believe there are four slots for engines in the power-pack car.

Transport for Wales have ordered a number of Flirts, which are similar to those in use by Greater Anglia, but they are tri-mode trains, that can run on overhead 25 KVAC electrification, diesel or battery power.

I speculate that they have one diesel engine and three batteries in the four slots.

This is a picture of the Flirt Akku.

I have enlarged the image and it would appear that the trains do not have a central power-pack car, but they do seem to have a lot of electrical gubbins on the roof.

This video shows the Class 755 train being tested at Diss.

It looks to have a much smoother roof line.

Could this indicate that the batteries on the Akku are placed on the roof of the train, as there is certainly a lot of equipment up there?

 

 

 

June 22, 2019 Posted by | Transport/Travel | , , , , | 10 Comments

A Lonely Electric Bus

I found this bus at its terminus by the old Barts Hospital.

It is an Alexander Dennis Enviro200ev.

They are built in Britain on a Chinese chassis from BYD.

This week, I read the obituary of Simon Norton, who was a mathematician, who had an interest in group theory and bus routes and timetables.

He could have worked out a strategy, of how to keep London’s fleet of electric buses fully charged.

Consider.

  • London’s single-deck routes are generally the shorter ones, so are probably ideal for electric buses.
  • My instinct is telling me, that if all small buses were to be replaced with electric ones, the tight network would show up places for charging points.
  • Would some be at the end of routes and some where several routes crossed?

It would be a fun calculation.

I suspect, I would solve it using a graphical method.

March 10, 2019 Posted by | Transport/Travel | , , | Leave a comment

More About Steamology Motion

In Grants To Support Low-Carbon Technology Demonstrators, I talked about a company called Steamology, who were given a grant by the Department for Transport to develop a method of converting hydrogen into energy.

The company is called Steamology Motion and in Issue 872 of Rail Magazine more details are given in an article, which is entitled DFT Hands Out £350,000 Each To Five Rail Green Schemes.

This is said in the article.

Steamology Motion, the final recipient, aims to create a new zero-emmissions power train for a Vivarail Class 230 train. The W2W system generates steam from compressed hydrogen and oxygen stored in tanks. The steam then drives a turbine to generate electricity.

The concept is aimed at being a ‘range extender’ able to charge onboard battery packs.

My mathematical modelling skills for this type of system have never been strong, but I’m sure that others will know how much hydrogen and oxygen are needed to charge a 200 kWh battery.

  • A quick search of the Internet reveals that small steam turbines could be available
  • I very much suspect, that as the system is a ‘range extender’, rather than a power unit to take the train hundreds of miles, that the physical size of the gas tanks will be smaller than those proposed by Alston for their hydrogen conversion of a Class 321 train.

I also don’t think that the DfT would have given £350,000 to the company, if the the physics and the mathematics weren’t credible.

Conclusion

If this technology is successful, I suspect it could have other applications.

February 11, 2019 Posted by | Transport/Travel | , , , , , , | Leave a comment

Mathematics Of Energy Storage

I am particularly talking about the sort of energy storage that is attracting the attention of Energy Storage Funds, that I wrote about in Batteries On The Boil As Fund Attracts Investors.

The Times article of the same name has this paragraph.

A typical 50-megawatt energy storage site of the kind the company intends to acquire hosts 19 containers each housing thousands of lithium-ion cells. A fully-charged container has the energy to boil 32,000 kettles.

This page on ConfusedEnergy.co.uk, says this.

We are often told to only use as much water as we need in a kettle and not to fill it to the top, but what are the potential annual saving in doing this. Well it takes roughly 4.5 minutes to boil a full (2 litre) kettle with a power rating of 3kW (kilowatts).

This means that to boil a kettle needs 0.225 kWh.

  • Boiling 32,000 kettles needs 7200 kWh or 7.2 MWh
  • Which means that the total capacity of the nineteen container energy storage facility is 136.8 MWh.

So the energy storage could provide the rated 50 MW for nearly three hours.

Lithium-Ion Batteries, Supercapacitors Or Both?

The article in The Times doesn’t mention supercapacitors.

If you watch the video in A Must-Watch Video About Skeleton Technologies And Ultracapacitors, Skeleton Technologies state the following about their ultracapacitors.

  • They are more affordable.
  • They generate less heat.
  • They have a higher energy density.
  • They can handle more charge/discharge cycles.
  • They have a faster response time, so would respond better to sudden demands.

I suspect there may be several operational and financial advantages, in replacing some of the lithium-ion batteries with supercapacitors.

 

 

November 10, 2018 Posted by | Energy Storage | , , | Leave a comment

Looking At The Mathematics Of A Class 170 Train With An MTU Hybrid PowerPack

From various sources like the Wikipedia entry for the Class 170 train and various datasheets and other Internet sources, I will try to get the feel of Class 170 train, that has been fitted with two MTU Hybrid PowerPacks.

Assumptions And Source Data

For the purpose of this post, I shall make the following assumptions about the Class 170 train.

  • The train has two cars, each with their own engine.
  • The train has a capacity of 150 passengers.
  • The train weighs 90.41 tonnes.
  • The train has an operating speed of 100 mph.

After conversion each car will have MTU Hybrid PowerPack with a 6H 1800 engine.

The data sheet for the MTU Hybrid PowerPack with a 6H 1800 engine, indicates the following.

  • Up to four 30.6 kWh batteries can be added to each module.
  • Each battery weighs 350 Kg.
  • Various sizes of diesel engine can be specified.
  • The smallest is a 315kW unit, which is the same size as in a current Class 170 train.

If I assume that the two diesel engines weigh about the same, then any increase in train weight will be down to the batteries, the mounting, the traction motor and the control systems.

But the hydraulic system will be removed.

Calculation Of The Maximum Kinetic Energy

I will now calculate the maximum kinetic energy of a fully-loaded train, that is travelling at maximum speed.

  1. Assuming the average weight of each passenger is 90 Kg with baggage, bikes and buggies, the weight nof a full train becomes 103.91 tonnes
  2. The train is travelling at 100 mph.
  3. Using the Omni Kinetic Energy Calculator gives a kinetic energy of 28.84 kWh.

So even if only one battery is fitted to each engine, there will be 61.2 kWh of energy storage per train, which will probably be more than enough to handle the regenerative braking.

The hybrid PowerPack will probably add some extra weight to the train.

Even if I up the total train weight to 120 tonnes, the kinetic energy is still only 33.33 kWh.

So half this amount of energy can easily be stored in a 30.6 kWh battery in each car.

I would be very surprised, if this train needed a larger engine than the smallest 315 kW unit and more than one battery module in each car.

Does The MTU Hybrid PowerPack Work As A Series Hybrid?

In a series hybrid, the operation is as follows.

  • The diesel generator charges the battery.
  • The battery drives the train using the traction motor.
  • During braking, the electricity generated by the traction motor is returned to the battery.
  • If the battery is full, the regenerative braking energy is passed through resistors on the train roof to heat the sky.

There will also be a well-programmed computer to manage the train’s energy in the most efficient manner.

For a full explatation and how to increase the efficiency read the section on series hybrid, in Wikipedia.

I’m fairly certain that the MTU Hybrid PowerPack works as a series hybrid.

Will The Train Performance Be Increased?

I suspect the following improvements will be achieved.

  • Acceleration will be higher, as it seems to be in all battery road vehicles.
  • Braking will be smother and the rate of deceleration will probably be higher.
  • Station dwell times will be shorter.
  • Noise levels will be reduced.

This video explains the thinking.behind the MTU Hybrid PowerPack.

These trains will be liked by passengers, train operators and rail staff, especially if they enable faster services.

Will The MTU Hybrid PowerPacks Be Difficult To Install?

MTU built the original engines in the Class 170 trains and their must be well over two hundred installations in this class of train alone.

So in designing the PowerPack, it would be a very poor team of engineers, who didn’t design the PowerPack as almost a direct replacement for the existing engine,.

Fitting the new PowerPacks then becomes a question for the accountants, rather than the engineers.

As both a UK and a German project have been announced in the last few days, it looks likely that MTU have come up with a one PowerPack fits all their old engine installations solution.

Conclusion

This project could be a really successful one for MTU and their owner; Rolls-Royce.

 

September 20, 2018 Posted by | Transport/Travel | , , , , , | 1 Comment

Mathematics Of A Bi-Mode Aventra With Batteries

This article in Rail Magazine, is entitled Bombardier Bi-Mode Aventra To Feature Battery Power.

A few points from the article.

  • Development has already started.
  • Battery power could be used for Last-Mile applications.
  • The bi-mode would have a maximum speed of 125 mph under both electric and diesel power.
  • The trains will be built at Derby.
  • Bombardier’s spokesman said that the ambience will be better, than other bi-modes.
  • Export of trains is a possibility.

It’s an interesting specification.

Diesel Or Hydrogen Power?

Could the better ambience be, because the train doesn’t use noisy and polluting diesel power, but clean hydrogen?

It’s a possibility, especially as Bombardier are Canadian, as are Ballard, who produce hydrogen fuel-cells with output between 100-200 kW.

Ballard’s fuel cells power some of London’s hydrogen buses.

The New Routemaster hybrid bus is powered by a 138 kW Cummins ISBe diesel engine and uses a 75 kWh lithium-ion battery, with the bus being driven by an electric motor.

If you sit in the back of one of these buses, you can sometimes hear the engine stop and start.

In the following calculations, I’m going to assume that the bi-mode |Aventra with batteries has a power source, that can provide up to 200 kW, in a fully-controlled manner

Ballard can do this power output with hydrogen and I’m sure that to do it with a diesel engine and alternator is not the most difficult problem in the world.

The Mathematics

Let’s look at the mathematics!

I’ll assume the following.

  • The train is five cars, with say four motored cars.
  • The empty train weighs close to 180 tonnes.
  • There are 430 passengers, with an average weight of 80 Kg each.
  • This gives a total train weight of 214.4 tonnes.
  • The train is travelling at 200 kph or 125 mph.
  • A diesel or hydrogen power pack is available that can provide a controllable 200 kW electricity supply.

These figures mean that the kinetic energy of the train is 91.9 kWh. This was calculated using Omni’s Kinetic Energy Calculator.

My preferred battery arrangement would be to put a battery in each motored car of the train, to reduce electrical loses and distribute the weight. Let’s assume four of the five cars have a New Routemaster-sized battery of 55 kWh.

So the total onboard storage of the train could easily be around 200 kWh, which should be more than enough to accommodate the energy generated , when braking from full speed..

I wonder if the operation of a bi-mode with batteries would be something like this.

  • The batteries would power everything on the train, including traction, the driver’s systems and the passenger facilities, just as the single battery does on New Routemaster and other hybrid buses.
  • The optimum energy level in the batteries would be calculated by the train’s computer, according to route, passenger load and the expected amount of energy that would be recovered by regenerative braking.
  • The batteries would be charged when required by the power pack.
  • A 200 kW power pack would take twenty-seven minutes to put 91.9 kWh in the batteries.
  • In the cruise the power pack would run as required to keep the batteries charged to the optimum level and the train at line speed.
  • If  the train had to slow down, regenerative braking would be used and the electricity would be stored in the batteries.
  • When the train stops at a station, the energy created by regenerative braking is stored in the batteries on the train.
  • I suspect that the train’s computer will have managed energy, so that when the train stops, the batteries are as full as possible.
  • When moving away from a stop, the train would use the stored battery power and any energy used would be topped up by the power pack.

The crucial operation would be stopping at a station.

  • I’ll assume the example train is cruising at 125 mph with an energy of 91.9 kWh.
  • The train’s batteries have been charged by the onboard generator, on the run from the previous station.
  • But the batteries won’t be completely full, as the train’s computer will have deliberately left spare capacity to accept the expected energy from regenerated braking at the next station.
  • At an appropriate distance from the station, the train will start to brake.
  • The energy of the train will be transferred to the train’s batteries, by the regenerative braking system.
  • If the computer has been well-programmed, the train will now be sitting in the station with fully-charged batteries.
  • When the train moves off and accelerates to line speed, the train will use power from the batteries.
  • As the battery power level drops, the onboard generator will start up and replace the energy used.

This sequence of operations or something like it will be repeated at each station.

One complication, is that regenerative braking is not one hundred percent efficient, so up to thirty percent  can be lost in the braking process. In our example 125mph train, this could be 27.6 kWh.

With an onboard source capable of supplying 200 kW, this would mean the generator would have to run for about eight and a half minutes to replenish the lost power. As most legs on the proposed routes of these trains, are longer than that, there shouldn’t be too much of a problem.

If it sounds complicated, it’s my bad explanation.

This promotional video shows how Alstom’s hydrogen-powered Coradia iLint works.

It looks to me, that Bombardier’s proposed 125 mph bi-mode Aventra will work in a similar way, with respect to the batteries and the computer.

But, Bombardier Only Said Diesel!

The Rail Magazine article didn’t mention hydrogen and said that the train would be able to run at 125 mph on both diesel and electric power.

I have done the calculations assuming that there is a fully-controllable 200 kW power source, which could be diesel or hydrogen based.

British Rail’s Class 150 train from 1984, has two 215 kW Cummns diesel engines, so could a five-car bi-mode train, really be powered by a single modern engine of this size?

The mathematics say yes!

A typical engine would probably weigh about 500 Kg and surely because of its size and power output, it would be much easier to insulate passengers and staff from the noise and vibration.

Conclusion

I am rapidly coming to the conclusion, that a 125 mph bi-mode train is a practical proposition.

  • It would need a controllable hydrogen or diesel power-pack, that could deliver up to 200 kW
  • Only one power-pack would be needed for a five-car train.
  • For a five-car train, a battery capacity of 300 kWh would probably be sufficient.

From my past professional experience, I know that a computer model can be built, that would show the best onboard generator and battery sizes, and possibly a better operating strategy, for both individual routes and train operating companies.

Obviously, Bombardier have better data and more sophisticated calculations than I do.

 

March 31, 2018 Posted by | Energy Storage, Transport/Travel | , , , , , , | 6 Comments

Mathematics Of The Lea Valley Lines

The mixture of Class 315 and Class 317 trains on the Lea Valley Lines are being replaced by new Class 710 trains.

Train For Train Replacement

London Overground currently has the following fleet, which work the Lea Valley Lines.

  • 17 x Class 315 trains – 75 mph
  • 8 x Class 317/7 trains – 100 mph
  • 6 x Class 317/8 trains – 100 mph

All these trains are being replaced by thirty-one Class 710 trains, which are 100 mph trains with a shorter dwell time at stations.

Time savings of over a minute, are claimed for each station stop, by other train manufacturers for their new generation of trains.

As one train is used on the Romford to Upminster Line, that leaves thirty trains to work from Liverpool Street to Cheshunt, Chingford and Enfield Town stations.

The Current Lea Valley Services

The current Lea Valley services can be considered to be two separate four trains per hour (tph) services to the following destinations.

  • Chingford
  • Edmonton Green with 2 tph extended to each of Cheshunt and Enfield Town.

Journey times are as follows from Liverpool Street.

  • Cheshunt – 39 minutes
  • Chingford – 27 minutes
  • Ednonton Green – 31 minutes
  • Enfield Town – 34 minutes

As an illustration of the slowness of some of these times, the fastest Cheshunt services take around twenty-five minutes, but they use the West Anglia Main Line, which has a higher speed limit.

Improving Journey Times

So how can journey times be improved?

The following factors will apply.

The Aventra Advantage

The Aventra and other modern trains will have the following advantages.

  • 100 mph operating speed.
  • Powerful acceleration and smooth regenerative braking.
  • Driver assistance systems to optimise train speed.
  • Level access from train to platform.

The last three factors will minimise the dwell time, when stopping at a station. Savings of up to three minutes have been claimed by some train manufacturers.

All Passenger Trains On The Routes Will Be Aventras

How much time this will save will probably be decided in practice.

Track, Station And Signalling Improvements

The operating speed of the routes is 40-75 mph , which could surely be improved.

Obvious problems include.

  • Level crossings at Bush Hill Park, Highams Park and Theobalds Grove.
  • Platform-train interface.
  • Provision of Harrington Humps.

A detailed analysis will probably be done to iron out any small time delays in running the routes.

Rewrite The Timetables For Aventras

Currently, the timetables are written so that they can be reliably run by the 75 mph Class 315 trains and also to allow for their possible presence on the routes.

How Much Can Be Saved?

This is a bit like asking how long is a piece of string, but assuming savings of a minute a station gives the following times.

  • Cheshunt – 24 minutes
  • Chingford – 20 minutes
  • Ednonton Green – 20 minutes
  • Enfield Town – 21 minutes

I would not be surprised if substantial time savings could be saved,

Liverpool Street Station

The pair of four tph services will mean that there will be a train arriving in Liverpool Street station every seven and a half minutes.

This should be no problem on two platforms, especially as all trains will be identical and designed for a fast turn-round.

Will they arrive and depart from a pair of platforms at Liverpool Street stations, like 2/3 or 4/5, so that passengers would know that their Lea Valley Line train always left from the same gates at the station?

This would surely make it easier for the train presentation teams!

Hopefully, by analysing the turning of trains, minutes can be saved.

Each Route In Detail

 

I shall now look at each individual route.

Liverpool Street To Edmonton Green

North of Hackney Downs station, in the Off Peak, the only trains on the route will be the following services.

  • Two tph between Liverpool Street and Cheshunt
  • Two tph between Liverpool Street and Enfield Town

These will be augmented in the Peak by some Greater Anglia limited-stop services stopping at Edmonton Green, Seven Sisters and Hackney Downs stations.

Current timings on this route are.

  • London Overground – 31 minutes with eleven stops using a 75 mph Class 315 train.
  • Greater Anglia – 23 minutes with two stops using a 100 mph Class 317 train.

As the distance between Liverpool Street and Edmonton Green stations is 8.6 miles, these timings give speeds of 16.6 and 22.4 mph respectively.

The following will speed up services on this route.

  • All trains on the route will be 100 mph Aventras.
  • The performance of the Aventras
  • Track, station and signalling improvements.
  • Driver assistance systems.

I suspect that my initial crude estimate of twenty minutes between Liverpool Street and Edmonton Green will be high.

Cheshunt Services

North of Edmonton Green station, the only service on the route will be the two tph service between Liverpool Street and Cheshunt.

As the route between Edmonton Green and Cheshunt is only 5.5 miles long, with just three stops, I wonder if when combined with the time between Liverpool Street and Edmonton Green, that the round trip time  could be reduced to under an hour, including the turn-round at both ends.

The current two tph service takes a few minutes over an hour-and-a half for a round trip from Liverpool Street, so three trains will be needed to run the service.

But if it could be done in an hour, then only two trains would be needed.

This level of speed improvement may seem ambitious, but the next generation of trains appear to be being built with it in mind.

Chingford Services

If the Chingford trains can do the trip reliably in twenty minutes, this would mean that a train could do a round trip from Liverpool Street to Chingford in under an hour, whereas now they take nearly an hour-and-a-half.

This means that four tph from Liverpool Street to Chingford needs either of the following trains.

  • 4 x Class 710 trains
  • 6 x Class 315/317 trains.

I doubt London Overground will park the spare trains in a siding.

It might even be possible to increase the frequency between Liverpool Street and Chingford. But this would probably need the removal of the level crossing at Highams Park station.

Enfield Town Services

North of Edmonton Green station, the only service on the route will be the two tph service between Liverpool Street and Enfield Town.

This is likely to be a route, where the return trip to Liverpool Street could be under an hour.

This means that two tph from Liverpool Street to Enfield Town needs the following trains.

  • 2 x Class 710 trains
  • 3 x Class 315/317 trains.

Conclusion

It does appear that on a rough look, the number of trains required to provide the current service will be less.

I think the three routes will need the following numbers of Class 710 trains to provide current services.

  • Cheshunt – 2 trains
  • Chingford – 4 trains
  • Enfield – 2 trains

As each train is usually eight-cars, then sixteen trains could be a minimum number to provide the current service.

But to do this, trains on each route must be able to do an out-and-back trip within an hour.

I think this could be possible and the extra trains will obviously be used to provide extra services.

 

 

 

 

 

 

 

September 25, 2017 Posted by | Transport/Travel | , , , , | 1 Comment