Could Hitachi Produce A Bi-Mode Class 385 Train?
Before I start, I’ll ask a simple question.
Is It Advantageous To A Train Operating Company (TOC) To Have Electric And Bi-Mode Versions Of The Same Train?
Their are two pairs of electric and bi-mode train types in the IK.
- The bi-mode Class 800 trains and the electric Class 801 trains.
- The bi-mode Class 769 trains and the electric Class 319 trains.
As the latter was specified jointly by a TOC and a ROSCO, I’m sure that it is advantageous for two closely-related versions to exist.
Hitachi’s New Trains
Hitachi will soon have four of their new train types in service in the UK.
Class 800 Trains – Electro-Diesel
Class 800 trains will soon be in service with Great Western Railway. The July 2017 Edition of Modern Railways says this.
The RMT union’s National Executive Committee has accepted Great Western Railway’s latest offer detailing the operational procedures proposed for the new Inter-City Express (IEP) due to start entering service in October.
So if that it is an affirmative, trains could be running by the end of the year!
Class 801 Trains – Electric Only
Class 801 trains will soon be in service with Virgin Trains East Coast. Wikipedia says service entry is planned to be 2017, but there is nothing definite on the Internet.
Although the new trains did make the cover of the July 2017 Edition of Modern Railways.
Note the headline of Azuma’s Are Coming!
I suspect though, that Sir Richard Branson will hate to be seen to have his trains in service after Great Western Railway.
Class 802 Trains – Electro-Diesel
Class 802 trains are just a version of the Class 800 trains, built not in Newton Aycliffe, but in Pistoia in Italy.
The July 2017 Edition of Modern Railways reports that two pre-production trains built in Japan arrived in the UK in June for testing, so the in-service date of December 2018 quoted in Wikipedia, should be achieved.
Modern Railways says this about the trains.
A key element in enabling fast delivery and subsequent entry into service is that the Class 802 trains are technically very similar to the IEP (Class 800/801) trains on order for both Great Western and East Coast services, featuring the same design of seats, kitchens and most components. Hitachi expects this to reduce significantly the time required for approvals prior to operational service. Key technical differences to the earlier lass 800 trains are different engine management software, enabling higher power output (700kW) from the MTU diesel power packs fitted with larger 120-litre urea (emission control) tanks.
Other features include larger fuel tanks, more powerful brakes and special features to cope with sea water spray at Dawlish.
Class 385 Trains – Electric Only
Class 385 trains are the babies of the four trains, being intended for Scottish routes between and around Edinburgh and Glasgow. Wikipedia gives an in-service date of December 2017.
Hitachi Have A Lot To Digest
Hitachi have the following trains on order for delivery by the end of 2019.
- 46 x 3-car Class 385 trains
- 24 x 4 -car Class 385 trains
- 46 x 5-car Class 800 trains
- 34 x 9-car Class 800 trains
- 12 x 5-car Class 801 trains
- 30 x 9-car Class 801 trains
- 46 x 5-car Class 802 trains
- 14 x 9-car Class 802 trains
That is a total of 252 trains involving a total of 1,456 carriages, which will have been built in three difference factories.
But at least they are all based on the same Hitachi A-train concept!
The Design Of The Class 80x Train
In Do Class 800/801/802 Trains Use Batteries For Regenerative Braking?, I did more than discuss the posed question.
I looked at the overall concept of the trains, as discussed in this document on the Hitachi Rail web site, which dates from 2014 and is entitled Development of Class 800/801 High-speed Rolling Stock for UK Intercity Express Programme.
The document provides this schematic of the traction system.
Note BC which is described as battery charger.
Reading the document in detail, I discovered the following facts.
- The 80x trains are effectively Plug-and-Play and automatically detect the configuration of a train, be it a single unit or two coupled together.
- Train length can be adjusted between five and twelve cars, by just adding or removing trailer or motor cars.
- In certain situations like train recovery, train length can be up to 24-cars.
- Coupling and uncoupling of two trains takes less than two minutes.
- Passengers are counted automatically. By a tiny Japanese robot walking up and down?
- Trains can be locomotive-hauled.
- The all-electric Class 801 train has at least one diesel power-pack per train for hotel power and emergency recovery in case of complete power failure.
The big omission is any talk of how regenerative braking is handled.
I have come to the conclusion, that the energy returned from the traction motors on braking goes through the APS (auxiliary power supply) to be used as hotel power, with any spare energy being stored using the battery charger in an appropriately-sized battery.
As a life-expired Control Engineer, I still know enough to realise that there is scope for a really intelligent control system, which takes note of myriad inputs to run the train in the most energy-efficient manner.
Inputs could include.
- Train position from GPS.
- Train route and terrain.
- Outside weather conditions
- Passenger load and expected journey patterns.
- Signalling and other train issues.
- Is electrification available?
- How much fuel is on board?
The train could be driven against the following.
- Minimum use of the diesel engines.
- Maintaining an appropriate level of power in the batteries.
- Optimal station stopping and restarting profiles.
- Driving to the terrain.
But probably most importantly, the trains will make sure they stick to the timetable.
Driving trains will be going through the revolution that flying planes went through some decades ago, where the pilots’ roles became much more of a supervisory one. But , of course they were there for emergencies or unexpected situations.
So How Do The Class 385 Trains Compare?
There is a document on the Hitachi web site, which is entitled Development of Class 385 Semi-customised/Standard Commuter Rolling Stock for Global Markets, which gives insights into Hitachi’s thinking.
This is the introduction.
The Class 385 is based on the AT-200, which was developed for global markets with the aim of providing flexibility of configuration while making maximum use of standardisation. It is a semi-customised model of a type common in global markets, with fewer components and greater standardisation of components achieved by adopting the “mother design” developed for the AT-300 (a typical example of which is the Class 800) and competitive lead times achieved by shortening the specification-setting process.
Note the close relationship between the Class 385 and Class 800 trains.
The Hitachi document gives a schematic of the Class 385 traction system.
Compared with that given for the Class 80x train, it is a lot simpler, with each bogie having its own converter unit. This is to allow both the three-car and four-car trains to have similar electrical layouts, that is easily modified for the shorter train, which has a smaller number of traction motors to save one and a half tonnes.
The document also says this.
The Class 385 uses the same main electrical components as the AT-300. However, the following electrical systems were adopted for use in the Class 385.
It then describes how the traction, brake and door systems have been modified.
In this Hitachi promotional video, power sockets and wi-fi are promised.
So where is the auxiliary power supply to power all these features and how is regenerative braking handled.
In the data sheet for the AT-200 train on the Hitachi web site, the following details are given.
- Three to twelve cars.
- 100 to 125 mph operating speed.
- Dual Voltage (25KVAC / 750 VDC / Battery)
As the Class 385 train is a member of the AT-200 family, could it be that like the Class 80x, it has similar electrical layout to the larger train?
So I have come to the conclusion that the regenerative braking energy goes to a battery, that is used to provide hotel power.
How Big Would A Battery For A Class 385 Train Need To Be?
In How Big Would Batteries Need To Be On A Train For Regenerative Braking?, I work through the calculation of the kinetic energy in a four-car Class 710 train, which would be Bombardier’s equivalent to a Class 385 train.
I said this.
To calculate the kinetic energy in the train, which will have to be transferred to the battery, we need the mass of the train and its velocity.
I’ll start with the velocity of the train.
As it approached a station, it will be at whatever is the appropriate line speed, which to make things easy I’ll assume is 100 kph or just under 28 metres per second.
In most cases after stopping and discharging and loading a few passengers, it will probably return to a similar line-speed to go to the following station.
The mass of each car of an Aventra, is found at several places on the Internet, including this entry in Wikipedia iwhich gives it as 30-35 tonnes. So the four-car Class 710 train could have a mass of 130 tonnes. Add 100 passengers at an average of 80 kg. each and this would make the mass 138 tonnes
Applying the standard formula gives a kinetic energy of 53240741 joules or in common-or-garden units 14.8 kilowatt hours. So the energy of an Aventra going at 100 kph could power a one bar electric fire for fifteen hours.
If you take the battery in one of London’s Routemaster buses, that has a capacity of 75 kWH.
As the specification for an Hitachi At-200 includes a battery option, fitting has probably been engineered.
Could A Diesel Powerpack Be Fitted Underneath A Class 385 Train?
I can only suppose that just as the Class 801 train has an diesel generator under one car, that the Hitachi design for the AT-200 train has provision for this feature in case an operator requires it.
If as I believe the Class 385 train has a similar electrical layout to the Class 80x trains, then incorporating a small diesel generator would not be a major redesign of the train.
But having a Bi-Mode Class 385 train might clinch a few sales.
Would A Bi-Mode Class 385 Train Have Uses?
There is no use building a train, that doesn’t have any uses.
The Class 385 train has been built with very careful considerable for weight. The design document says this.
Railway businesses in the UK include ROSCOs, TOCs, and track maintenance and management companies.
The TOCs pay fees, called track access charges, which are based on the weight of rolling stock and the distance travelled, and are obliged to pay the track maintenance and management company for the electrical power consumed in train operation. Because lighter trains put less load on the track, they incur lower track access charges. As lighter trains also consume less electrical power, there was strong demand from the TOC to make the rolling stock lighter, right from the pre-contract stage.
So if the bi-mode version of the Class 385 is a bit heavier because of the diesel powerpack, the train will be more expensive to run, which is probably acceptable to the TOC.
Looking at Scottish rail routes, there are several services in the area between Edinburgh and Glasgow, which will be run on partially-electrified lines.
Conclusion
Due to the modular nature of these Hitachi trains, I wouldn’t be surprised if it is possible to fit a small diesel power pack under a Class 385 train.
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