Would It Be Sensible To Build London Overground’s Lea Valley Trains As Eight-Cars?
It has been reported that getting the new Train Control Management System on the new Class 710 trains is proving troublesome. It also still needs to be updated for multiple working, as is reported in this article in Rail Magazine, which says.
He (Jon Fox) also said that the TCMS will need further updating for the Class 710/1s, which will be required to operate in multiple on West Anglia inner-suburban trains from Liverpool Street. Asked when they would enter traffic, he said: “Not predicting, but it will be this year.”
As these trains will always work in pairs of two four-car trains, why not build them as eight-car trains?
- Yrains would consists of two driver cars and six intermediate cars.
- There would surely be less testing needed.
- New trains could be in service earlier.
Software for multiple working could be pushed back few months, until needed.
Would the cost of manufacture be lower?
The Formation Of A Class 710 Train
This morning, I was able to look at the plates on all four cars of a Class 710 train.
Here is the formation of the train.
DMS+PMS(W)+MS1+DMS
The plates on the individual cars are as follows.
DMS – Driving Motored Standard
- Weight – 43.5 tonnes
- Length – 21.45 metres
- Width 2.78 metres
- Seats – 43
The two DMS cars would appear to be identical.
PMS 
-Pantograph Motored Standard
- Weight – 38.5 tonnes
- Length – 19.99 metres
- Width 2.78 metres
- Seats – 51
The signifies a wheelchair space.
MS1 – Motored Standard
- Weight – 32.3 tonnes
- Length – 19.99 metres
- Width 2.78 metres
- Seats – 52
It is similar in size to the PMS car, but has an extra seat.
These figures add up to the unit figures you would expect.
- Weight – 157.8 tonnes
- Length – 82.88 metres
- Seats – 189
But what else can be said?
All Cars Are Motored
All four cars are motored, which is not an arrangement seen very often in UK electrical multiple units.
- Most British Rail units like Class 317, 319 and 321 trains have only one motored car.
- Five-car Class 800 trains have two trailer cars and nine-car trains have four trailer cars.
- Eight-car Class 700 trains have four trailer cars and twelve-car trains have six trailer cars.
Class 345 trains which are also Aventras, have eight motored cars and only one trailer car.
I suspect that it is an arrangement that gives advantages, over the weight and cost of the extra motors.
Less Force Between Wheel And Rail
The tractive and braking force between the wheels and the rail will be less to get the same acceleration and deceleration, as the force will be divided between all traction motors and wheels.
Does applying the power at all wheels mean that the train accelerates and decelerates faster, thus cutting station dwell times?
Does this mean that wheel slip, which damages wheels and rails is less likely?
Are the lower power traction motors more reliable?
Can A Motored Car Be Changed Automatically To A Trailer Car?
Suppose a traction motor or its controlling system packs up, can the train’s central computer switch it out and effectively convert the errant motored car into a trailer car.
On a 710 train, that would mean a 25 % loss of power, but surely the train has sufficient power to be driven to the next station?
Equalisation Of Forces Between Cars
The forces between the four cars must be equal and possibly low at all times, as you have four identical individually-powered, computer-controlled vehicles moving in unison.
Does this give passengers a smoother ride?
Does it mean that walking between cars is an easier process?
I think so and I can only think of the problems of getting a four-person pantomine caterpillar working properly!
A Logical Way To Power A Train
Could it be that this is the logical way to power a train, but you need precise computer control of all cars to take full advantage?
It strikes me that getting it right could be a very difficult piece of computing, so has this been causing the delays for the Class 710 trains?
I don’t think we’ll know the answers to all my questions, until Bombardier publish a full authorised philosophy.
Twenty Metre Long Cars
British Rail designed a lot of trains to be eighty metres long give or take a metre. So there are a lot of platforms in the UK, that can accommodate an eighty-metre long train.
All of the London Overground routes, where these trains will run have platforms that can accommodate 80, 100 or 160 metre long trains.
So they could be run by a single train or two trains running together as appropriate without any expensive platform lengthening.
The Two Driving Cars Appear Identical
This must be logical.
Many older electrical multiple units have different driving cars.
Sod’s law states that one type will be less reliable than the other, so you’ll end up with a shortage of trains.
But if both driving cars are identical, you have much less of a problem.
What Will Be The Formation Of a Five-Car Class 710 Train?
If all cars are to be powered then it will be.
DMS+PMS(W)+MS1+MS2+DMS
MS2 and MS1 would be identical.
Would you really want to add a new trailer car into the fleet to complicate maintenance?
Why Are The Trains For The Lea Valley Lines Not Eight-Car Trains?
On the Lea Valley Lines, London Overground have said that they’ll generally run two four-car trains as an eight-car train.
In Latest On The New London Overground Class 710 Trains, I discussed the possibility of changing the order to a number of eight-car trains and felt there could be advantages.
- Higher passenger capacity in the same train length.
- An eight-car train would contain only two DMS cars instead of four.
- Trains could be built as two four-car half-trains, to improve reliability.
- Passengers would be able to walk the full length of the train.
Bombardier and London Overground must have analysed this and as they have more information than I do, they have come to a different conclusion.
Is there for instance, a safe procedure, that uses the operational train to transfer passengers to a safe place and then drag the failed train to appropriate parking?
- With an eight-car train, you’d have no operational train to take passengers to safety.
- With two four-car half-trains, as in Crossrail’s Class 345 trains, would you have other problems? But the Croosrail trains are designed for a long tunnel, with difficult evacuation problems.
There must be a very valid reason.
Conclusion
The Class 710 train has been well-designed and is not your normal suburban train.
What Is The Kinetic Energy Of A Class 710 Train?
I finally got a good look at a Class 710 train at Gospel Oak station this morning.
The picture shows the plate on the end of a DMS car.
- The weight of the train is 157.8 tonnes. Note that the four-car Class 378 trains weigh 172.1 tonnes.
- 700 passengers at 90 Kg each with baggage, bikes and buggies would be 63 tonnes.
- That would be a total weight of 220.8 tonnes.
- The operating speed is shown as 75 mph., which is the same as the Class 315 train, that many Class 710 trains will replace.
Using the Omni Kinetic Energy Calculator gives a kinetic energy of 34.5 kWh.
For completeness these are the figures for different speeds.
- 90 mph – 49.4 kWh – Operating speed of a Crossrail Class 345 train.
- 100 mph – 61.3 kWh – Operating speed of many electric multiple units.
Note that the amount of energy is proportional to the square of the speed.
What Do The Kinetic Energy Figures Show?
These are a few of my thoughts.
What Is Regenerative Braking?
A full Class 710 is travelling along at 75 mph, ihas 34.5 kWh of kinetic energy. Whenit needs to stop at a station, this energy has to be dissipated.
With normal friction brakes, the energy will be converted into heat and wasted.
But with regenerative braking, the traction motors are used in reverse to generate electricity.
This electricity is generally handled in one of three ways.
- It is passed through resistors on the roof of the train and turned into heat and wasted.
- It is fed back into the electrification and used by nearby trains. This needs special transformers feeding the electrification.
- It is stored in a battery or other energy storage device on the train.
The last method is the most efficient, as the stored energy can be used to help restart the train and regain line speed.
Can The Lea Valley Lines Electrification Handle Regenerative Braking?
This question must be asked, as if the lines can’t then running trains with batteries could be the best way to handle regenerative braking and improve efficiency and reduce the electricity bill.
It should be noted, that the Chingford and Enfield Town routes are not shared with any other trains, so running Class 710 trains on these routes may have advatages in the maintenance of the electrification, if the trains handle the regenerative braking.
On the Cheshunt route, there are also some Greater Anglia services, but these will generally be run by Class 720 trains, which are also Aventras.
On the other hand, the electrification on the Gospel Oak to Barking Line has probably been installed to handle the reverse currents.
Do Class 710 Trains Have Regenerative Braking?
Search the Internet for “Class 710 train regenerative braking” and you find little in addition to my ramblings.
But other Aventras, like Crossrail’s Class 345 trains have been stated to have regenerative braking.
I also repeated my views in an article in Rail Magazine, which I described in I’ve Been Published In Rail Magazine.
No-one has told me that they disagree with my views and I was talking rubbish!
So I will assume that Class 710 trains do have regenerative braking!
The Aventra’s Electrical Systems
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.
This was published eight years ago, so I suspect Bombardier have refined the concept.
But even in 2011, Bombardier were thinking about energy storage on the train.
How Much Storage Would A Class 710 Train Need?
As I said earlier, I train would need sufficient energy storage to store the kinetic energy of a train.
As my calculations show that a full train travelling at the maximum speed of 75 mph, then the energy storage for this version of a Class 710 train must be able to store at least 34.5 kWh, at all times.
The size of the on board energy storage could be around 40-50 kWh, which is readily available in a lithium ion battery, that has been designed for transport use.
Where Would The Energy Storage Be Placed?
The extract above says that two cars hold the electrical systems.
These pictures show the pantograph car and driver car next to it.
Note that underneath the pantograph car is a transformer.
So are these, the pair of cars, the extract describes? They certainly could be!
This is a selection of pictures of the underneath of the driver car.
Note.
- There are two large boxes with latches under both driver cars.
- Next to these boxes is a smaller box. At the pantograph end of the train, it is open and looks like a cooling system for the two boxes
- At the other end of the train, the smaller box appears to have a blanking plate, so perhaps the boxes are empty.
The only sensible use I can think of for the boxesis to store the batteries or capacitors.
I
I would estimate that each of the four large boxes.
- Is about a metre wide.
- Is about 0.3 metres high.
- Is sized to fit within the 2.7 metre width of the train. Perhaps 2.5 metres.
These give a column of 0.75 cubic metres.
Bombardier used to manufacture a Primove 50 kWh battery, which was built to power trams and trains, that had the following characteristics.
- A weight of under a tonne.
- Dimensions of under two x one x half metres.
Were these boxes under the floor of the driver cabs of the Class 710 train designed to hold a Primove 50 kWh or similar battery?
Four batteries could give the train as much as 200 kWh of energy storage.
But surely for trundling along the Gospel Oak to Barking Line. a smaller battery capacity would be sufficient. I suspect that you fill the boxes with how many batteries you need and the computer does the rest.
Perhaps, just one 50 kWh battery would be enough! This could explain, why the cooling system appears to be blanked off at one end of the train.
Could The Batteries Be Used To Power The Class 710 Train?
In an article in the October 2017 Edition of Modern Railways, which is entitled Celling England By The Pound, Ian Walmsley says this in relation to trains running on the Uckfield Branch, which is not very challenging.
A modern EMU needs between 3 and 5 kWh per vehicle mile for this sort of service.
So a 50 kWh bsttery would give the following ranges with these consumption rates for a four-car Class 710 trains.
- 3 kWh – 4.2 miles
- 4 kWh – 3.1 miles
- 5 kWh – 2.5 miles
It looks to me, that battery power would be possible over the extension to Barking Riverside station, which is about a mile long.
Battery power would also other uses.
- Moving the train to a safe place for passenger evacuation, when the overhead electrification fails.
- Moving the train in a depot or sidings, without overhead power.
- Running innovative on-board services for maintenance and train preparation, when the train is parked overnight.
Reliable battery power has a lot of uses on a train.
West London Orbital Railway
The West London Orbital Railway would have less than ten miles of lines without electrification, with several electrified miles on either side.
I believe that Class 710 trains with the right amount of batteries could bridge the gap and make a massive difference to rail transport in North and West London.
I think that jumping a gap of a few miles on battery power, may well be easier than doing an Out-and-Back service..
A Flexible System
As it appears, each Class 710 train has got four battery boxes, I suspect that batteries can be installed as to the needs of the route.
- Standard operation on Gospel Oak to Barking, Watford DC Lines and Lea Valley Lines could be one or two batteries to handle regenerative braking.
- Out-and-Back to Barking Riverside station ,might need two batteries.
- West London Orbital services might need three or four batteries.
These battery boxes also could be designed to allow an easy and quick change of battery, as batteries on buses have given Transport for London trouble in the past.
Conclusion
Bombardier’s design of the Aventra has been designed with battery operation in mind, which opens up lots of possibilities!
And Then There Were Three!
This morning, I went to Gospel Oak station to look at what was running on the Gospel Oak to Barking Line.
I’d just watched two Class 710 and two Class 378 trains run the 10:10, 10:35, 10:50 and 11:05 trains to Barking, when another Class 710 train come through, by-passing Platform 3 and going straight on towards Barking.
So that must mean there’s at least a third Class 710 train, either being tested, training drivers or accumulating mileage.
Checking on Real Time Trains, it appears that the train passed Gospel Oak station at 11:11 and then ran all the way to Barking station, where it arrived at 11:53, which would have been the time that the missing 11:20 train would have arrived in Barking.
I can’t find any trains disappearing, but it looks like a train joined the service in the missing 11:20 slot and another train disappears back to Willesden Depot, thus creating a slot for another train.
The outcome is the following.
- Passengers seem to be getting at least three trains in every hour in each direction.
- London Overground have at least two and possibly three Class 710 trains running between Gospel Oak and Barking.
Baldrick would be proud!
Abbey Line Passing Loop Proposed
The title of this post is the same as that of an article in the June 2019 Edition of Modern Railways.
Bricket Wood station used to be an important station on the Abbey Line, with grand buildings and a passing loop to allow trains to run a thirty-minute service as opposed to the current inconvenient train every forty-five minutes.
Consultants have now said that a traditional passing loop, with a second platform and a bridge would cost up to £10million, which is probably not viable.
The Penryn Solution
The article says this about the consultants’ alternative solution.
The platform at Bricket Wood be lengthened such that trains stop at different ends of a single platform, similar to the solution adopted in Penryn on the branch line from Truro to Falmouth, which would help to minimise costs.
This Google Map shows Penryn station.
Note the long single platform in the station.
This section in the Wikipedia entry called Signalling, gives a full explanation of the method of operation at Penryn.
Bricket Wood station already has a platform, that can take a comfortably take a four-car Class 319 train, as this Google Map shows.
There also appears to be space to put a second track alongside the current single track.
Does The New Track Need To Be Fully-Electrified?
Battery trains are coming and there are several trains that can use both electric and battery power under development, in the UK, Europe and Japan.
Bricket Wood station is 3.5 miles from the Watford Junction end of the Abbey Line and perhaps three miles from the St. Albans end.
n an article in the October 2017 Edition of Modern Railways, which is entitled Celling England By The Pound, Ian Walmsley says this in relation to trains running on the Uckfield Branch, which is not very challenging, as is the Abbey Line.
A modern EMU needs between 3 and 5 kWh per vehicle mile for this sort of service.
So if a four-car electric-battery hybrid train was to handle the whole of the 6.5 mile route, it would need a battery of between 156-260 kWh to go between Watford Junction and St. Albans Abbey stations and back.
But supposing trains used the current electrification between Watford Junction and Bricket Wood stations to both power the train and charge their batteries.
- The trains would only be doing six miles on batteries, so the battery would be between 72-120 kWh.
- Trains would raise and lower their pantographs at Bricket Wood station.
- No new electrification would be required.
It might be preferential to remove electrification between St. Albans Abbey and Bricket Wood stations to save maintenance costs and improve safety.
Should The Abbey Line Be Transferred To Transport for London?
There have been suggestions in the past, that the route be transferred to Transport for London.
I’ll leave the politics aside, but electric-battery hybrid versions of London Overground’s Class 710 trains, which will soon be serving Watford Junction station would be ideal.
Conclusion
There are certainly, affordable ways to improve the Abbey Line.
And Finally!
They have been a long time coming, but today two Class 710 trains, started running on the Gospel Oak to Barking Line.
I took these pictures.
They certainly stand out with their large orange noses.
A few thoughts on various topics.
Doors And Controls
The doors are all double and wide as they should be for easy entry.
There are also full door controls on each side of the door and a door opening button in the door itself.
So on a crowded train, there won’t be the problem, you get on some trains, that the buttons are blocked by a large person standing in the way.
Information Displays
They are clear and very much follow the style of the displays on the Crossrail trains.
Although, they do have a clock, that seemed to be liked by other passengers and myself.
I also suspect the displays can be used advertising.
Noise
Like the Class 345 trains, they are quiet inside.
Seats
The longitudinal seats are as comfortable as those of their elder siblings; the Class 378 trains.
There are also lots of armrests.
As on those trains, passengers find their own place to put their legs and the passage up the middle of the train seems to stay free.
There are also no perches either side of the door, as in the Class 378 trains. It this to cut out canoodling?
USB Sockets
There isn’t a large number and they are only accessible from a few seats.
This picture shows the sockets on a Vivarail Class 230 train.
I think each armrest should have one.
Wi-Fi
I tested it and it worked
The Train Software
If I was designing something like a train, a tram, a bus or a car, the vehicle would have a backbone, that was compatible with the Internet.
The train software, that seems to have caused the delay could even be an operating system, like the one on your computer or phone.
In my experience, operating systems are very difficult to write, but once they are working, the following is possible.
- They work for all compatible computers, phones or trains.
- They can analyse the hardware to see what they’ve got connected.
- A large team of programmers can write compatible additions, just like thousands write apps for mobile devices.
I also believe that testing operating systems work as they should is one of the most difficult things to do in computing.
I don’t believe that the delay to the Class 710 trains because of software problems has been overly long in my experience.
Complex systems just take an awful long time to get write.
The good news though, is that if Bombardier have got their design right, they may well have cracked the computer systems for all other Aventras.
Conclusion
They tick a lot of boxes and I like the design.
I also feel that if Bombardier have solved the software problems, then Aventras could be delivered in a steady stream.
London Overground Timetable Changes After Delay In New Trains
The title of this post, is the same as that of this article on the Watford Observer.
This is the first paragraph.
Passengers could face some difficult journeys to work over the next few months after a delay in delivering new electric trains.
The late delivery of Class 710 trains have struck again.
Instead of four trains per hour from May 19th, the service will stay as three trains per hour on an unusual 15, 15, 30 time interval.
Probably more annoying than a disaster.
