Steam locomotives: Coal burners V.S. Oil burners

[jettrainfan]

Hello, i was on trainorders today and read an article about oil burners, didn't give too much info past efficient (oil burnt per mile). This led me to questioning, what's the difference between Oil burners and coal burners? I know that western railroads favored oil cause it was cheaper out there and that's about it. Also, how do you fire an oil burner? I don't think you can have a oil can and just stick it through a hole or something... Any info would be great!

Thanks!

[J3a-614]

Howdy, Jet,

I'm going to start on the assumption you're familiar with coal-burning steam.  Coal burners burn their coal on a grate, much like a stove or home furnace.  Smaller engines, up to a certain size (I'm afraid I don't recall it, it's defined by weight on drivers) were hand-fired.  Some of these locomotives could be fairly large, like Pennsy's K4s, which had 70 square feet of grate area, but that was really too large for reliable hand firing, and the Pennsy was actually ordered to install stokers on them.  (It turned out to be a good move, as it enabled the engine to develop its full power continuously and reliably.)

Mechanical stokers for larger power worked with a screw type conveyor (a large auger) running out of the tender, through a tube with joints, up to a firing table (a plate) inside the door of the firebox, where steam jets sprayed the now crushed coal onto the fire.  Other controls, such as grate shaking bars to knock ashes out of the fire, remained the same as they did for hand-fired engines.

An oil-burner had a tank installed in the area occupied by the coal bunker, with appropriate pipes and hoses leading to a burner in the firebox.  Feed was either by gravity or, in the case of Southern Pacific's cab-forwards, with a fuel tank that was pressurized to about 5 psi from the air brake system.  This was because the firebox on a cab forward was some distance ahead of the oil tank on a l-o-n-g locomotive, and on the steep grades of that railroad, it was quite possible for the firebox to be a good deal higher than the tank, hence the need for force feed.  The burner itself was a set of nozzles that mixed oil with steam to atomize the oil (break it into small droplets), blowing it into the firebox in a mist that burned with a roar.

An oil burner with steam in it could be "lit off" just by turning on the steam and oil and throwing a burning rag in the box, but a cold engine either needed a fire to be started with wood to get steam up or had to have an outside source, such as a roundhouse boiler or another locomotive, to put steam in first.  The burner itself was controlled by a valve on the fireman's side, and was very responsive compared with coal burners; the valve handle was on a large quadrant in the cab, and moved horizontally, like the valves on the air brake stand.  You could turn the fire up or down, like on a gas stove.  However, partially because of that rapid response, the fireman had to be on his toes all the time; set the fire for a relatively modest demand, have the engineer open up, and the steam pressure went way down.  Keep the fire too big, and you had huge clouds of black smoke (too rich) and roaring safety valves.

Other quirks of oil fired steam included the necessity of keeping the fuel warm with a steam heating coil in the tank.  The oil used in steam service was "Bunker C," or "residual"oil--the black gunk left in the bottom of the refining still after all the lighter stuff, such as gasoline and kerosene, had been refined off.  That stuff was like tar, and had to be heated to about 70 degrees to get it to flow, but if you got it too hot, it would boil over, and that goo would run down the outside of the tender, and supervisors would wonder about your skill as a fireman. 

There's a little more, but I have to run for now, will be back when I can.

 

[richg]

http://www.sdrm.org/faqs/hostling.html

Probably more than you want to know about coal and oil fired boiler's. Lots of links to study and save.
Many reasons for the difference.

http://privatelee.qrobe.it/search/?q=coal+fired+vs+oil+fired+locomotives

Rich

[J3a-614]

Well, I'm back, and I must give compliments to Rich G for his links, particularly the first one, which has much more detail than I would have been able to provide, much of which is also common to coal-burners, such as the balance that must be reached in the use of steam, water, air, and fuel to get things right. 

A few other things:

One, a disadvantage of oil-burning steam engines is that they lack cinders!  Yes, that sounds strange, as most people hate that black, oily sand that coal-burners throw around, but they have the useful property of scouring out soot and carbon from inside the tubes and in certain places of the firebox.  An oil burner can soot itself up inside to where the heat from the fire doesn't do such a good job of boiling water.  For that reason, oil burners also carried a box of sand in the cab, with a small scoop; at convenient places, typically where the engine would have to work hard (such as an ascending grade), the fireman would throw a few scoops of sand into the firebox through a hole in the firedoor.  The draft would suck the sand through the engine and scour out the soot.  You can imagine the smoke effects you got when this was being done! 

The other item was about the oil getting too hot.  Supposedly, you used your nose to make sure this didn't happen.  If you could smell sulfur, the oil was too hot and in danger of boiling.  One fireman on the SP recounted how he and his engineer were in a siding when a passenger train pulled by a beautiful orange, red, and black Daylight locomotive roared past--with a huge, black, sticky stain running down the sides of the tender, and strong smell of sulfur.  He wondered what was wrong with the sinuses of the crew, who should have picked up that smell. 

Fuel consumption was technically less with oil than with coal, because oil had more BTUs (British Thermal Units, a measure of energy contained in fuel) per pound than coal, but consumption was still enormous compared with diesel locomotives, and especially to something smaller, like your car.  A large oil-burner, like a 4-8-4, would burn about 10 to 12 gallons of Bunker C per mile; a first-generation diesel would consume maybe a quarter of that, perhaps three gallons per mile.  Net cost advantage was a bit less; diesel fuel in this time period went for about 10 cents per gallon, while Bunker C in some cases went for 5 cents per 42-gallon barrel.  For comparison, a coal burner would get, depending on conditions and the quality of the coal, anywhere from 10 to 20 miles per ton of coal.

Water consumption was typically about 200 gallons per mile for the steam engines, and as noted in Rich G's linked story, it was best if given some sort of treatment to prevent rust, scale, and foam inside the boiler.  That was another expense item for the railroads in steam days, and it could be a very notable item if you had a railroad like the Santa Fe, with a lot of desert mileage where you had to haul water in.  Multiply that by a railroad with a lot of traffic, and that's an ocean of water to haul into the desert.

Have fun.

[richg]

Early American oil fired loco. Just before the cab forwards out west.

http://www.ironhorse129.com/Projects/Engines/NPC_21/NPC_No21.htm

These locos where a real kick. They burned Bunker C. A real difficult oil to handle at normal temps.
Search You Tube and you will find videos of the prototypes in operation.

http://privatelee.qrobe.it/search/?q=union+pacific+gas+turbines

Many times the tenders looked like a real mess if overfilled.

http://www.american-rails.com/gas-turbine-locomotive.html

How these gas turbines actually operated.

http://www.northeast.railfan.net/turbine_faq.html

Rich

[J3a-614]

Rich, your turbine link reminded me of this clip on YouTube. 

Check out what happens at 2:21:

http://www.youtube.com/watch?v=dPh1JkIhoOk

[Johnson Bar Jeff]

However, partially because of that rapid response, the fireman had to be on his toes all the time; set the fire for a relatively modest demand, have the engineer open up, and the steam pressure went way down.  Keep the fire too big, and you had huge clouds of black smoke (too rich) and roaring safety valves.

Hmm. So maybe that's how they deliberately got Sierra #3 (aka the Hooterville Cannonball, etc.) to throw off so much black smoke and steam for TV and movie work. There's an oil tank hidden under that pile of wood on the tender that you see on TV and in the movies. 

[Doneldon]

J-J:

You can also make heavy smoke by throwing a shovel of sand into the firebox.

                                                                                                           -- D

[Johnson Bar Jeff]

J-J:

You can also make heavy smoke by throwing a shovel of sand into the firebox.
                                                                                             -- D

Sure enough, as J3a pointed out. Easy to imagine how black the smoke got when you scoured out the soot with the sand. But I'm thinking of the steam effects, too.

[jettrainfan]

Thanks everyone for the info! Really enjoyed that story that guy wrote about starting up that steamer, found it quite interesting. With me, there's never too much information if its train related. 

[richg]

Thanks everyone for the info! Really enjoyed that story that guy wrote about starting up that steamer, found it quite interesting. With me, there's never too much information if its train related. 

From that article you can see how hard it is on a loco to completely cool down and then be restarted.
The NYC Niagara locos did not cool down. The fire was dropped. Men in asbestos suits entered the firebox to clean out the scale while the loco was still in steam.
Many roundhouse could pipe steam into a loco if the loco did not completely need to be cooled down.
Many roads would also bank the fire if coal fired.

Rich

[phillyreading]

Another problem with oil burning is keeping the burning area clean as mentioned with adding sand to the firebox.
There were a few other problems with steam locomotives, but fuel consumtion and water con sumtion were major issues before the diesel or electric engine.

Don't know how bad it was for railroads but home oil burning furnaces, without yearly cleanings, tend to explode because of soot build-up from the oil being burned. This has happened several times in the northeast US during the winter months.
A similar problem used to occur with cars, the spark plugs were not kept clean by doing regular tune-ups, so the engine would diesel or knock and ping after being turned off because there was a small amount of carbon still on fire at the tip of the spark plug.  House oil burning heaters had the same problem without being cleaned, reason they exploded or blew up is because the oil was sent to the burner area and there was a small fire already there, instead of being lit by the ignitor coil, thereby causing a small explosion because it caught fire before the time it was supposed to burn.

Lee F.

[electrical whiz kid]

Hi, Lee;
Thanks for the heads up about home furnaces.  As an electrician, I occasionally get called in to a furnace problem, and in talking with the furnace techs, someimes learn some pretty interesting facts.
All of these discussions about steam reminds me of just how easy it was/is to set a "motor" (electric locomotive) up to run.  With the New Haven as an example, the dispatcher would put a call in from New Haven to the plant engineer at Cos Cob with the dispatch schedule, and the engineer would provide the capacity via extra power output when needed.  That all done, the motor engineer raised the pan, and off they went.  that is an oversimplification, but it gets the point across;  Just as easy as that!
Rich

[Johnson Bar Jeff]

Just as easy as that!

Until the power fails. ...   

[ebtnut]

Electrification was a two-edged sword.  The installation of the necessary infrastructure was VERY expensive, especially if it included power generating stations.  Once up and running, electric power was very efficient.  If the traffic density could justify it (i.e., NH, PRR) it was worth it.  The Milwaukee Road bankrupted itself installing its electric lines, one of the reasons they never connected the two divisions.