We caught a special on PBS (during pledge week) about various scenic railroads the public can ride. I missed this part, but my family was watchign and claims one train skirts the Grand Canyon (or, was it Royal Gorge, CO) and runs on veggie oil? Which railroad was this? And, so…just what kind of fuel is veggie oil? I would imagine cheap, but highly inefficient. What’s the SD about this?
Diesel engines can run on vegetable oil. It’s undoubtedly a type of biofuel which can be processed vegetable oil.
A diesel engine is a (high) compression ignition instead of using a spark. Waste vegetable oil is a viable fuel option with just a few modifications.
It was a sub-culture not that long ago. Converting a diesel passenger car to run on waste vegetable oil was very popular option when diesel fuel was $4 to $5 per gallon. 1980’s Mercedes’ were very popular candidates for the conversions.
See:
http://www.grease4uel.com/index.htm
The Grand Canyon Railway recently started running their steam engines on veggie oil:
This is somewhat more unusual than running diesel engines on vegetable oil, which is probably why it was worthy of mention on a PBS special.
Yep, although the similarity between veggie oil and diesel is still relevant, since many of the locomotives in the later parts of the steam era were oil-fired and ran on fuel oil that was very similar to diesel. It looks like this locomotive was originally a coal-burner, but the GCR converted it to an oil burner when they bought it back in '89, since getting large quantities of fuel oil is easier than coal in that part of the world. Sounds like major modifications weren’t really necessary to run it on veggie oil-- the challenge was just the logistics of getting that much of the stuff.
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Yeah, kind of sad since I really like those old W123 chassis Benzes and you see a lot of them that got trashed by half-assed WVO installations.
The big reason why the fad died out, though, wasn’t the easing of diesel prices but the skyrocketing cost of WVO. It used to be you could just fill 'er up for free behind the local burger shack, but in places where WVO got popular eventually some entrepreneur would start paying to haul the stuff off and then selling the cleaned oil. From there, supply and demand did its thing and it didn’t take too long for the price of clean ready-to-go WVO to get up to about the same price as diesel.
It’s actually not inefficient at all. Overall it’s a pretty decent fuel.
A diesel engine actually has a better thermal efficiency than a gasoline engine. This is why trucks still mostly use diesel engines. They convert more of the energy into movement and less of the energy into waste heat. The problem with diesel engines though is that they tend to have a much narrower power range than a gasoline engine, so while the diesel wins at highway driving, the gasoline engine wins at city driving.
Most diesel engines can run on vegetable oil without any modifications at all, but in the long run it’s not very good for the engine. Vegetable oil freezes solid at temperatures which are common in much of the U.S. during winter. Also, when the vegetable oil is cold it tends to clump, which leads to a lot of unburned gunk that gets deposited inside the engine. The simple solution for this is to heat the vegetable oil before putting it into the engine, so many diesel vehicles that have been modified to run on vegetable oil have two tanks, one for diesel fuel and one for vegetable oil. The engine starts on diesel fuel and runs on it until the oil heater (powered by waste heat from the engine) is hot enough that you don’t have the clumping problem any more. Then the fuel line is switched to the vegetable oil tank and the vehicle runs on that. When you stop, you switch back to diesel (so you don’t have to worry about clumping or the oil gelling up in the fuel lines) and then shut down the engine.
Another solution is to treat the vegetable oil chemically, and turn it into biodiesel.
While an internal combustion engine is a bit picky, an external combustion engine, like a steam engine, can usually run on just about anything that burns with very few modifications. As GreasyJack said, they probably didn’t need to do much to make the locomotive burn oil instead of coal.
When I was going through college and grad school, I was the engineer of a steam-powered tourist railroad. Our locomotive was originally built as a wood burner, but had been converted to burn propane, and I can confirm that it’s a pretty easy process to convert. For us, it meant installing a propane tank in the tender, removing the grates in the firebox, installing a crop burner (3, really), and connecting the lines.
For an oil-burner, you’d need an atomizer, which can be steam powered, but that’s about the only real difference I can think of. Most of the time, with the oil-burners I’m familiar with (burning Bunker C fuel) the initial steaming up is done by soaking some rags in oil and starting a fire in the firebox until the fuel lines are warm and/or there’s enough steam pressure for the atomizer, at which point you can light the oil injectors.
Vis-a-vis biodiesel: Amtrak did a yearlong experiment on locomotive 500 a couple of years ago, since it was in captive service on the Heartland Flyer between Ft. Worth and Oklahoma City. I haven’t seen the data analysis but I believe the road foreman said the experiment had positive results.
No fuel like an old fuel.
Actually, a lot of railroads converted from coal to oil in their steam engines in the early part of the 20th century, at roughly the same time that navies tended to convert from coal to oil for their steam engines.