Which pollute more -- steam or diesel?

R

RobertInOntario

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Mar 22, 2006
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Toronto, Ontario, Canada
In light of all the "green" talk these days I've been wondering which type of locomotive pollutes more -- steam or diesel? I'd always assumed that steam locos must be pretty bad because they're burning coal and putting carbon into the atmosphere, and that modern diesels must be fairly clean.

But yesterday, a friend at a LHS said that he thought the steam engines actually polluted less than diesels because the type of pollution is more natural. They don't produce the type of greenhouse gases (that diesel and gasoline engines do) that remain in the atmosphere.

So I thought I'd toss this question out here and perhaps those who are more knowledgeable on these subjects could respond. I'm also an avid outdoors person (hiking, canoeing) so I'm concerned about being "green" as well.

It will be very interesting if steam engine pollution is actually less damaging than diesel pollution -- then we could form lobby groups to re-introduce steam locos!! :D
Rob
 
Steamers will never make a comeback due to the immediate effect on the bottom line. Maintenance costs were reduced so much that even perfectly servicable steamers were scrapped, and diesels were mass-purchased to replace them.

Both steamers and diesels use fossil fuels (coal or oil, and diesel fuel), and both release carbon and oxides of nitrogen to the atmosphere. The efficiency of both diesel generators and coal/oil fired steamers is relatively poor, although I would guess that the diesels get better "milage". (However, I believe that the fuel used per tonne of goods used is still better than trucking, so maybe we should lobby in favour of trains over trucks ;)).

The Green Goat (Canadian designed switcher) is getting a lot of good reviews since it has basically changed the way the generator is run to produce electricity for the traction motors. See http://www.railpower.com/products_hl_howitworks.html. It uses a much smaller, more efficient engine that runs only to recharge batteries, rather than varies its speed based on the needs of the loco's job. It also does not need to sit idling once the batteries are charged.

The only really "environmentally friendly" steamer would be a wood burner, as it uses a truly renewable resource. And that's only if the railways agreed to manage their fuels source - tree plantations - so that the cycle is truly completed.

There are other impacts though - manufacturing of steel used in the loco still produces environmental degradation (mine, transport, refining, etc). Even the Green Goat is full of batteries that need some sort of handling/processing at the end.

Sorry about that... ;)

Andrew
 
Rob the problem is that coal puts off sulpher...the only way to really stop that problem and go back to steam would be like they have done with Navy ships and go nuke with steam turbine to turn the the alternators. But the anti nuke ppl would have a fit.

If you are really concerned about pollution you should really research it on your computer. Its amazing how much pollution is blamed on the internal combustion engine when in fact about 80% of the air pollution in Ca is from factories. But to make the smaller companies comply they would be to make them go broke. So the state and federal government is not going to force mass unemployment and a recession to clean it up, it's much easier to blame the automobile.

There is a lot of junk science involved in the anti pollution ring. And we cannot solve the problems with it until the real science is out and we are willing to pay for small companies to clean up, force mass transit and other things to take place. That is going to take tax dollars and not protest, or lies.


At least thats my take on it.

Rick
 
It isn't going to happen at all, since the majority of the uncontrolled pollution takes place in countries that have no intention of doing anything about it.

The Soviet Union polluted itself and the oceans around it literally at will. as Russia Rebiorn they strill do. China pumps out enough pollution every year to make up for all of the non-industrialized nations on Earth and the Third World nations as well. Meanwhile, the Third World nations are pumping it out by the metric tone every second of every day. You can't even breathe in Mexico city.

Locomotives in First World nations are the last thng any of us need to worry about. As for diesels, tourists are not lining up to ride diesels because they have no beauty and no soul, the things that made steam engines part of us forever.
 
Its amazing how much pollution is blamed on the internal combustion engine when in fact about 80% of the air pollution in Ca is from factories.
Click to expand...

That's what I was getting at when I talked (wrote?) about the steel processing and manufacturing phases. It takes more energy to make your car (from raw resources to finished automobile) than that car will burn in gas over the LIFETIME of the car...! Think about that...! :eek: hamr

Andrew
 
I think the steam engine has the potential to be less polluting than the conventional diesel electric. A steam engine by nature is a furnace. If we were building steam engines today, they would probably have an electronic control on the fuel delivery that would monitor exhaust gasses and produce perfect combustion. With external combustion you don't have to fire the gasses, make power, and exhaust them hundreds of times a minute. I'm presuming here that the modern diesel elctric prime mover is a low rpm diesel like we used on the ship I was on in the Coast Guard where we are talking about an engine that turns less than 1000 rpm at full throttle. With a steam engine, you could burn the fuel as hot as needed for as long as needed to produce complete combustion. I would imagine that pollution controls on a modern steam engine would be similar to pollution controls on a modern fossil fueled power plant. Of course as has been mentioned, the maintainance requirements and operating expense of steam engines were such that we will never go back. I think hybrid technology, like the Green Goat is the wave of the future.

Regarding trains vs trucking for freight hauling, the only problem the railroads have is railroad management. It is much more economical to ship by train than it is by truck, but historically the railroads have been as slow to change as the military. Following the American Civil War, the U.S. Army was still issuing the single shot Springfield rifle to the troops to fight the indian wars even though the Winchester repeater was in production and the preferred choice of civilians. Why, because the generals knew and liked the Springfield and didn't trust the "new fangled stuff." In the same way the railroads method of operation was developed in the 1860's and railroad management has been fighting change tooth and nail since. Someday the railroads will actually figure out how to move products with the same efficiency as the trucking companies, and get it distributed when it reaches its destination in a timely manner, and then long distance trucking will be a thing of the past. Much of the nonperishable freight is travelling by rail, but probably less than 10% of the perishable freight is going by rail because the railroads can't guarrantee getting it across the country and delivered before it spoils.
 
If I were betting I would have to vote for the horse days. Though seeing a trolley or train powered by a horse is cool I think it might cause some time delays.

Which pollutes more is relative between coal and diesel. There are more factors to this than what just comes out of the smoke stack. Each in its own right causes environmental damage when it is extracted from the ground and processed into fuel.

[FONT=&quot]Green is fine but if that is the only factor then probably we should be using horses again. I would think that a train using any fuel in general would result in less pollution only because of the tonnage that can be transported for the total pollution produced.
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Thanks for your feedback! I'm not seriously advocating the return of steam for modern freight or passenger use. Even though it's a nice idea, I realize that modern diesels are easier to maintain & operate. For example, it takes several hours to bring a steam loco to full steam & they require a LOT of maintenance in general.

So it seems that steam locos might be slightly less harmful to the environment than diesels? (I agree that increased railroad use in first world countries is actually good for the environment because it's an efficient mode of travel.)

Thanks!

Rob
 
OK, let's start from the beginning, with efficiency.

The main advantage diesel offers over steam is thermal efficiency. This is the ratio of energy in:energy out, or how efficiently you convert the energy in the fuel to mechanical energy. A simple single-expansion steam locomotive gets about 5-7% efficiency. Adding a condenser can raise this in a locomotive to about 14%. About the best anyone ever managed was Andre Chapelon's experiments in France after WWII, where with compounding and condensing he was able to get close to ~30% efficiency.

A simple diesel has a thermal efficiency of about 30%. Right off the bat it's got an obvious advantage over steam. With electronic fuel injection and combustion control, I suspect the number is even higher now. Diesel is a more energy-dense fuel than coal, although it comes close to bunker-oil. But burning bunker oil to heat water in a steamer is less efficient than using it in internal combustion.

Open combustion of coal or oil is less efficient than internal combustion, because it's at 1 atmosphere pressure, whereas in interal combustion, the pressure is higher, and combustion can be more complete.

There is no such thing as "natural" pollution... Does a wood-burning steamer pollute less than a forest fire? Yes, maybe a bit, because the wood burns at a higher temperature in the firebox, but it's still throwing out soot (carbon) and ash (incompletely combusted wood) as well as CO2 and other gasses.

Because steamers and diesels are burning complex organic molecules in addition to C02 and water (the byproducts of complete combustion), and because neither yields 100% complete combustion, you also get various nitrogen and sulphur compounds, which add to the pollution. When you factor in the thermal efficiency, while the steam and diesel may be producing the same compounds, the diesel produces less than the steamer for a comparable amount of energy.


Your friend apparently doesn't have a clear understanding of what "greenhouse gasses" are. The main GG's are water vapour, carbon dioxide (CO2), methane, nitrous oxide, sulphur hexaflouride, and hydrocarbons. So actually, if you include water vapour, a steamer will even more greenhouse gas than a diesel per unit energy.

Where things get confused is that there's a host of pollutants that are not greenhouse gasses, but are smog gasses, like sulphur dioxide and nitrous oxide. These are much more harmful in the short term, and are produced both by steam and diesel. Again, with a higher thermal efficiency, the diesel will produce less of them per unit energy produced.


So, apart from efficiency, steam locomotives are, as previously mentioned, much higher-maintenance machines than diesels. Diesels are able to utilize their maximum horsepower over a wider range of speeds than steam. As well, steam engines are harder on track than diesels because of the pounding force of the reciprocating gear. You can't easily MU steam locomotives (at least not with 1 crew!), and because they're more efficient, and diesel is almost twice as energy-dense as coal, diesels can go much further between fuel stops.

OK, end of lecture... ;)
 
Perhaps the future of rail transport is to go lighter and smaller - the local deliviery version of trucks. I am tihnking of small branch lines serviced by self-propelled rail vehicles that break off on their own from a "convoy" system similar to a freight train of today and make an entirely computer-controlled delivery to an industry. Empties or loads could rejoin anytime on the track and drop off again at their destination, or team up for a larger requirment. Unit trains serving single-product bulk shippers like mines, granaries and so forth would remain more or less as is.

I think the addition of advanced computerized controllers and the expansion of the rail network is the key to the future. I would be riding a train to and from Denver and Colorado Springs, if there were one available with a convenient schedule, convenient distance to walk from my home and connections to get me where I need to go within the sprawling megalopolis of today.

Europe manages very well with their rail and bus system, but we seem terminally afflicted with the NIH Syndrome.
 
MM,

Such a thing exisits. A friend showed me a self-propelled flat car that had a computer and GPS link-up so it could travel by itself over the rails to various destinations that did not warrant an entire train coming to town. Unfortunately, I cannot locate the link, but I'll do a search...

Andrew
 
Going back to horses is no solution: a massive problem in cities before the automotive era was horse dung on the streets! Not just a little bit, but mounds of dung in the street and along the side of the road, add water (rain) and you get a filthy, soupy disease-carrying mess. The lives of horses pulling streetcars were typically short and brutal: even with the tiny single-truck streetcars of the day, a horse would get worn out within a couple of years. Electric streetcars were much more cost-effective and many times faster.

The "Green Goat" is the locomotive equivalent of a hybrid car...and since they are made from recycled Geep body frames, they save energy even in the construction of locomotives.
 
Here's a bit of info.

First passenger service. It's hard to believe that there is still a place for these (seemingly) small companies:

http://www.edwardsrailcar.com/ -> tourist railways
www.coloradorailcar.com -> commuter lines

Freight:

http://en.wikipedia.org/wiki/CargoSprinter -> text
http://www.bahnbilder.de/bilder/1519.jpg -> picture

There is one other one I can't find right now that looks just like a flat car. But the railways have had lots of experience with self-propelled cars and remote operation, so it should not be anything new...! Cranes, MoW cars, and remote operations like CTC and even switching in yards via R/C.

Andrew
 
oldtanker said:
Rob the problem is that coal puts off sulpher...the only way to really stop that problem and go back to steam would be like they have done with Navy ships and go nuke with steam turbine to turn the the alternators. But the anti nuke ppl would have a fit.
Click to expand...
That would be really cool to see though.
Can you imagine how fast a nuke powered train could move?
 
There's another reason for not going back to horses - not only do their droppings pollute the land and water, their gasses pollute the air as well. In some of the dairy regions of California, this has become a major problem as the number and density of dairy cows has become a major source of smog:

http://news.nationalgeographic.com/news/2005/08/0816_050816_cowpollution.html

There's no information I've seen on whether horses expell as many gasses, but if they were bred in sufficient numbers to equal the amount of horsepower pulling Class 1 trains, I imagine the 'exhaust' would be quite pollutant. Not to mention that the farmers growing their feed are still burning gas or deisel in their tractors and harvesting equipment, and using any number of fertilizers on the crops to increase the yeild to meet the new demand.

Long haul, long and heavy trains which don't stop often are the most effecient means of moving bulk goods. It's the 'don't stop often' part which seems to be a problem today.


Chris
 
Good post, MJ.

The Europeans have enormous incentive to get "articulated lorries" - semi-and-trailer rigs - off of their already crowded road systems, and they have an exiasting extensive rail asystem that still serves small towns as well as large. We, on the other hand, have been steadily tearing up our trackahge for the last half century or more.

As for the atomic train concept, no offense, but I can't think of a single true need for a nulcear powered train, and a lot of reasons why it would be a bad idea. And as far as how fast it could go, no faster than the track is engineeed to take no matter how much power is available, and I'm not at all sure how beneficial it is to humans to rocket through the landscape at 200 or more miles-per-hour in the first place.

What ever happened to "Getting there is half the fun", "Relax and smell the roses", and all that other stuff? We are already a nation of stress-cripples, consuming a major protion of the world's supply of psycotropic meds, as it is.

Look at what has happened to the aircraft industry in their stampede to keep making money by cramming more and more people into larger and larger, faster and faster aircraft. They are going broke, while the cost continues to climb and service is non-existent. Air teravel, which was once pleasant, is now like being loaded into an over-crowded cattle car and fired from a cannon.

No thanks. I would be perfectly happy to have roomy, comfortable seats, large view windows, decent food and a restful experience with a top speed of no more than 100 mph on the straight-aways, prefererably less. I like arriving relaxed and rested, not staggering off the transport and vomiting at will from stress, lack of sleep, crappy foood and the sheer mental pressure of too many rude people in too small a space.

Lab rats kill each other in conditions we seem to take for granted in our transportation industry.
 
When I brought up the nuclear power it wasn't about speed. A small reactor could power a steam turbine which in turn can turn an alternator to power the electric drive. If run correctly and built to high standards they would be safe, clean and efficient. They have powered experimental cars like that.

The fuel used could be used to build a dirty bomb but isn't weapons grade. And yes there would be security issues with that.

Another solution would be a nuke power plant and electric trains the power plant being much easier to secure and then it's just overhead wires.


The big problem there is educating the masses and getting over the hysteria linked to anything nuke.

Rick
 
The speed bit wasn't my idea' i merely commented on it.

However, since we are talking about pollution, do we actually need another source of spent nuclear fuel, quite a few sources associated with this scheme inhj fact since we can assume mpore than one locomotive, which we will also have to safely bury for 10,000 years?

Do we need to worry about a train crash leaking radiation? Do we want "green" groups, tree huggers, anti-nukes and every other whacko in America barricading the tracks and demonstrating?

Do we want sources of nuclear power running around out in the open where the Islamofascist lunatics might be able to get their hands on them or sabotagethem t to lay waste to an entire area? Or will be posting armed guards on every nuclear engine on the rails and flying choppers along overhead to guard them 24/7?

We couldn't even stiop a bunch of loonies from hijacking four airliners in broad daylight and killing 3000 people. According to the latest reports from Homeland Security and citizen watch groups, the airports are no safer today than they were on 9/11. How will we secure train engines? Build big bunkers to park them in, and armor them so that no one can even approach them?

We have nuclear shipping containers that can stand a full speed train crash, to be sure, but will they withstand a fanatic with a rocket launcher? Will the public tolerate the potential risk?

In my mind, given the lunatic climate of mindless violence that dominates the 21st century,
and the number of fanatics who have no greater desire than to kill as many of us as possible, the risk's far outweigh the benefits.

Far better to build nuclear reactors to electrify catenary systems and run the trains that way, if push comes to shove.
 
Very true, but we should do something. Solar power currently is a joke. #1 they don't make enough cells in a year to really do anything with plus the amount of land you would cover is unreal. #2 the tree huggers have already sued to try to put a stop to wind power because birds might fly into the blades. #3 I did mention nuke plants and electric engines just not in the same words. #4 the same people who drive 2 blocks to work would be the same ones out there protesting a nuke plant, never mind a car, truck or train running a reactor on board.

I really get a kick out of the BIO fuel or green fuel advocates. Have they stopped to think how many more acres of land will be cleared and planted by farmers once corn and bean prices go up never even thinking about the extra chemicals that the farmers will use to get a better crop.

You are not going to force the general population into mass transit. Look at the light rail system the the twin cites is putting in. Hasn't been there long and they are complaining that not enough people are using it. But they are going ahead with construction of more of it. And the word is that most of the passengers are gang bangers. Others are afraid to ride it. People are not just going to stop driving.

Rick
 
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