Green Goat Gives Diesel Trains A Serious Head Butt
by Dominic Muren, Philadelphia, USA 
on 05. 9.05
While a huge part of the global economy runs on commercial trucking, a substantial percentage is still taken care of by railways. One of the major benefits of a rail-style system is that once you get the freight moving, it stays moving. This minimal stopping means high efficiency for the engines responsible for pushing the cars cross-country. But in the freight yards where loads of freight have to be shuttled around to change tracks, the cars stop and start a lot. With tens of thousands of pounds of freight being pushed around, that can mean huge energy losses for the "Goats" -- the freight tug engines which do the pushing. Luckily, a Canadian company has an answer to this problem: Brawn and Batteries...
Railpower Technology has rolled out a new Diesel-electric hybrid engine. Dubbed the Green Goat, this burly little fella is set to shake things up in the rail yard.
Diesel Electric isn't new for trains. Most Diesels on the tracks today actually run a generator with their fuel, and use that electricity to drive the wheels. The problem is starting up: If you think your little Corolla has trouble getting up to speed in first gear, imagine what a starting hundreds of thousands of pounds of freight moving would be like. You'd wear through a transmission a week. Instead, using electricity allows the motors to run at a constant gear ratio, and speed is controlled by varying power to them.
But even so, these trains suffer from huge losses because the large diesel engines needed to deliver the starting power (up to 3500 horsepower!) are kept on even when the power needs are nowhere near this level. This idling engine loss leads to massive amounts of fuel being burned unnecessarily.
The Green Goat substitutes a much smaller 250hp engine-generator setup, but also adds storage batteries capable of 2000hp for high-power starting. After the generator is no longer needed, it simply shuts off, eliminating idling losses. The train can then run off power from the battery banks.
This hybrid setup creates almost unbelievable advantages:
- Improved visibility because of lower generator housing.
- Improved traction, because of heavy weight of batteries.
- 80-90% reduction in NOX and Particulate emissions.
- 30-80% fuel savings
- First year is virtually maintenance free, and subsequent upkeep is simple because of small, light, standard parts
- Smaller generator makes operation very quiet
With tens of thousands of switching locomotives around the world, the introduction of the Green Goat could mean serious fuel savings, and cleaner air.
:: Railpower's Green Goat [by DM]
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The diesels are cut down to the amount required at the wheels. While a switch engine does idle a fair amount of the time, I suspect the environmental damage done by the batteries themselves is comparable to the amount done by burning the extra fuel. How much fuel is required to make those batteries? Where are the chemicals from? How are they disposed of? More importantly - how long do they last? That's what worries me about hybrid vehicles, too - I think we need to eliminate the personal vehicle culture.
Ben-
Good questions, and ones I'm not really expert enough to answer (I mean, I'm just a mechanical engineer, not some awesome Canadian Railroad engineer :)
But in this case, it may not be totally bad news. The website says that many of the switching trains on the rails today are from as long ago as the 1950's. With a maintained life like that, it's probable that the embodied energy in these new engines (without the batteries) could be recovered.
As far as the environmental costs of these batteries go, a benefit of lead acid is that they are such an old technology that there are real options for re-conditioning, and re-using the lead and acid in the batteries, rather than trowing them away when their useful life is over.
I think that the real benefit of this system is that it reduces the necesity of using large amounts of petroleum-based power. I assume that most of the energy that went into producing the batteries and other high-embodied-energy systems in this train could (but maybe didn't yet) come from renewable sources.
As far as the personal vehicle culture goes, that's an entirely different fish. You could argue that we really should do less inter-continental shipping, and focus on local economies. I really don't know one way or another.
All I know is our crews like them alot. They start and stop fast. They are quite and don't make you suck diesel fumes all day. The only problem is they are new. And like any "A" model it breaks down every other day. That's alright. They'll get the bugs out.
I drive a Hybrid Car, it is known as a Honda Insight, it has a 1000 cc engine and a 144Volt NMH battery pack, I routinely achieve 95 mpg (imperial gallons) on long runs, my other car a small Nissan Micra hatchback 1275 cc engine, achieves 55 mpg on the same run.
I recall Green Goat style technology being discussed in 1978, I was working for an Petrol Refinery at the time, all the research engineers were very enthusiastic about it, 20 years later the japanese brought out the first production hybrid cars
The hybrid concept works!