steam engine expenses

keh

Well-known Member

Just wondering how the operating expenses for a steam tractor were back in the day. Years ago a friend commented about his father running a sawmill with a steam engine and burning the slabs and maybe sawdust. Not much fuel expense there. I have heard of thrashing crews in the wheat belt burning the straw, but I suspect they also brought along a load of coal. An old sawmill man near me had an old steam engine but I don't ever remember it running. I think it was in need of repairs which may answer my question about expenses because a steam engine looks like it would need a lot of expensive repairs from time to time.

My father said he remember hearing a steam engine running a sawmill, probably before World War I. He said when it was sawing through a big log the engine would start puffing slower and slower and when it cameto the end the puffs would speed back up.

I do barely remember steam trains. When starting off the old engine would give out a long puff, maybe spin the drivers so that the engineer would have to drop a little sand from the sand tubes on the tracks, and then the train would pick up speed. A steam locomotive at speed would have a very rapid puff-puff along with clouds of smoke.

KEH
 
The steam engines puffed because the cylinder exhaust was routed out the flue to increase draft, so the harder you worked them, the more heat it created.

The boilers would require repair and inspection at an ASME shop, I would think that is not cheap, other parts would need to be built.
 
Can you buy a can of steam?

They used what ever cheapest combustable available and delivered tremendous torque using belt drive systems. I believe they would run a long time with normal lubrication.
 
My Dad hauled water to the steam engine; that kept him busy all the time the steam engine ran.

He said that they didn't like to burn straw as the straw burned so fast they could barely feed the boiler fast enough to keep up the steam. The other factor was the straw resulted in too many sparks coming out the exhaust. Fire was always a risk in the stubble fields so they did everything they could to reduce the risk.
 
A good friend of mine who has a traction engine said his one engine requires as much maintenance as a handful of gas tractors. Back in the day when steamers were new or at least newer they didn't have to worry about rusted thin flue sheets like they do today but they still had to be vigilant in other areas. High pressure steam can cut through pipe threads in a hurry if a leak develops in a steam line or valve and can burn a bystander. A poorly maintained steamer can be very dangerous without even blowing up.
 
I remember my grandpa telling me of at least one barn in the area burned down from sparks while thrashing, another incident when someone tied down the safety valve to get more pressure and the entire engine blowing up.
 
They worked well, but used a lot of fuel, water and had high maintenance. Same reasons the railroads converted.
 
The fuel may be cheap, but the engines are not. Once you realize that most of the purchase cost of a piece of machinery is determined by the materials which go into it, it becomes apparent that steam engines (the boilers, specifically) are very expensive. A 20 hp steam engine will likely weigh in excess of 5000 lbs empty, while a 1950's 20 hp gas tractor can easily weigh less than 2500 lbs. That is a 2-to-1 cost difference in materials alone.
Also, maintenance is a major problem when you have open mechanisms which are exposed to lots of water and dirt, while being only marginally lubricated.
Plus, you have no instant performance. First you must warm the thing up and start to make steam, then you must anticipate load by adding fuel at the proper rate. Too little fuel and the pressure drops, and too much fuel causes the pressure relief valve to blow, wasting a bunch of stored energy that you just fed into the firebox.
Poor efficiency is another issue. When you have a lot of surface area, you have a lot of area that can transfer heat. With an uninsulated boiler like the ones on vintage steam engines, you are constantly loosing gobs of heat to the surrounding air. With this style simple boiler you are lucky to get 15% efficiency out of the fuel you burn. Almost any old gas tractor will give you 25% efficiency when working at rated load.
Then there is the work that is required to feed it. Steam tractors need lots of two things to operate; fuel and water. Anyone who has a wood stove knows the constant work that is required to keep it going. Now figure that your wood stove has more than 10 times the appetite, and that it is also constantly leaking a few gallons of water each minute. Now you have an idea of how much work it is to feed a small steam tractor that is working.
 
How come the coal boxes on steam tractors are so small then? They look like they hold a couple hundred pounds of coal at most. That can't possibly be enough to run all day.
 
If land mobile,steam powered equipment was so good we'ed still be driveing Stanley Steamers and rideing the rails behind steam driven locomotives.













 
Railroad literature might be a place to find detailed comparisons of operating costs between steam locomotives and diesel locomotives. In the 1950's steam locomotives in good working condition were cut up for scrap because they cost too much to operate.
 
(quoted from post at 05:14:39 09/03/14) How come the coal boxes on steam tractors are so small then? They look like they hold a couple hundred pounds of coal at most. That can't possibly be enough to run all day.

Nope. It is enough to last about 1 hour, which is all the water supply is good for as well. They used to water and fuel the steam engines on the go when plowing. I am pretty impressed with the horses that would walk along side a working steam engine as you pumped water from the water wagon to the engine.

Steam gets in your blood and you quickly become addicted to them. I have a 1/2 scale model, but it is as much work to run as a full size one, but is easier to haul. You do need to realize that my "toy" weighs 4500 lbs and can pull 2-14 plows. My scale model can easily go through 50 gallons of water and 100 lbs of coal in an hour if I am working it.
 

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