Have Bombardier Got A Cunning Plan For Voyagers?
In the July 2018 Edition of Modern Railways, there is an article entitled
Bi-Mode Aventra Details Revealed.
A lot of the article takes the form of reporting an interview with Des McKeon, who is Bombardier’s Commercial |Director and Global Head of Regional and Intercity.
This is a paragraph.
He also confirmed Bombardier is examining the option of fitting batteries to Voyager DEMUs for use in stations.
The
Voyager family of trains has three members.
The trains have the following characteristics in common.
- They are diesel electric multiple units.
- Each car is powered by an underfloor Cummins QSK19 diesel engine of 750 hp/560 kW.
- They are capable of 125 mph running.
- Some trains are fitted with tilting, which isn’t used.
- The trains have rheostatic braking.
- They meet or could easily meet the latest accessibility regulations for passengers of reduced mobility.
- Train length appears to be flexible and cars seem to be able to be swapped around in a particular class.
I think it is true to say that the operators have a few problems with these trains.
- Some passengers think the trains are rather cramped.
- There is also a noise and vibration problem when the engines are working hard.
- There have been problems with seawater getting in the resistor banks for the rheostatic braking on Class 220 trains at Dawlish.
- CrossCpuntry would welcome extra capacity.
- Both operators would probably welcome better fuel consumption on the trains.
How Would You Fit A Battery To A Voyager?
All these trains seem to be fitted with
rheostatic braking.
Effectively, the traction motors generate electricity when they work in reverse to slow the train. On a modern train this electricity is either returned through the electrification to power other trains or stored in a battery.
But on these Voyagers, it is passed through resistors on the roof and used to heat the sky.
Consider these facts for a four-car Class 220 train.
- The train has an operating speed of 125 mph.
- Each car has its own diesel engine.
- The train has a weight of 185.6 tonnes.
- The train has seats for two hundred passengers.
- If we assume that each passenger weighs 90 Kg. with their baggage this gives a total train weight of 203.6 tonnes.
Calculating the kinetic energy of the train for various speeds gives
- 75 mph – 32 kWh
- 90 mph – 46 kWh
- 100 mph – 56 kWh
- 125 mph – 89 kWh.
Every time a train stops, this energy goes to waste.
The simplest thing to do, would be to divert this energy to an appropriately sized battery in each car. As there is four cars in the train, a battery of 50 kWh in each car would probably be sufficient.
If the battery was full, then the energy would still go to the resistors on the roof.
You’ve now got a full battery, but how would you use the energy in a productive manner?
The easiest and probably best thing to do with it, is to power the hotel functions of the train like air-conditioning, lights, doors and toilets. This is an approach taken by Hitachi on their
Class 800 trains, as this diagram confirms.
The diagram is contained in this
document on the Hitachi Rail web site, which is entitled
Development of Class 800/801 High-speed Rolling Stock for UK Intercity Express Programme.
The document is a fascinating read.
Using the energy to power the traction motors and move the train might be possible, but I suspect it might be too complicated and expensive.
The simple system of the braking energy charging the battery and then using this energy for hotel power has advantages, both for Hitachi and Voyagers.
- The engines generally won’t need to run in a station to provide hotel power,as Des McKeon noted.
- The control electronics would be reasonably simple.
- Many of the existing expensive components like engines and traction motors probably wouldn’t need to be changed.
- There might be maintenance savings on the brakes.
- Less fuel will need to be expended to provide hotel power.
- If say the train has to halt perhaps because of a signalling or track fault, hotel power can be provided without running the engines.
- If batteries are supplying the hotel power, the train may have more power for traction.
I obviously don’t know how independent each car is from the next, but if each is independent, then there could be further advantages in converting, testing and maintaining the cars.
Conclusion
It looks to be a good plan.
