Every once in a while, there will be a picture of a diesle locomotive in Trains Magazine that has an unusual amount of smoke coming from it. In the notation, the writer will often say something to the effect that the unit in question is obviously not pulling as hard as the other units.
Why is this the case? What causes the excessive diesle smoke and how much does it affect their tractive effort/horsepower?
Thanks,
Gabe
Excessive smoke can come from a number of sources:
Turbo lag, often associated with Alco locomotives, is a cause that occurs then the throttle is advanced and the engine burns rich until the turbocharger catches up to force in more air.
Carbon buildup occurs when the engine has been idling for a prolonged period. Clouds of blue smoke result when the engine is opened up and blows the carbon particles out of the exhaust system.
Heavy smoke under load is also an indicator of turbo trouble.
Alot of U and B units I find smoke alot. On a video though an ex Conrail C40-8W pulling and NS autorack train with another NS unit through Attica, smoke as if it was a steam locomotive.
If it was just after ideling, carboin built up in the stack, and forced out with the exhust, sometimes, creating fires.
Could be a bad ring, piston, or as said, turbo problems.
Change the rack settings and keep 'em moving!
Our new METRA units (MP series) have already begun to smoke quite a bit upon acceleration, where they did not when new.
Seems like everyone pretty much summed it up ! The color of the smoke is important. white smoke is raw fuel. I often look at the radiator shutters to see if thier stuck open, preventing the engine from reaching operating temp. White smoke can also be a sign of a dead cylinder. Black smoke is mostly carbon from too large amounts of fuel, not enough air.
Randy
LOcal steel plant here (Cayce, SC) has a MP15 that does its switching. It smokes like a steamer from one stack (black smoke), hardly any smoke from the other stack. WUWT?
I’ve also tried to figure where this loco came from; its orange, with a HUGE 960 (engine number) on side of hood. No other markings except spray can lessee marks on cab.
EMDs are notorious for “souping” during extended periods of idling. There’s a few things going on that contribute to this. The cylinder pressure is lower, so the rings don’t seat as well. The injection stroke is slower (but shorter, too), so, perhaps the fuel doesn’t atomize as well or burn as thoroughly, and the cylinder liner wall is a bit cooler, so the oil on the liner wall is a bit thicker. The net result of this is a whole lot of goop laying up in the exhaust passages and manifold. Once you throttle out, it starts to boil off and burn out. After a few minutes, you should have clear stack, if not, then you have bigger problems. An EMD turbo all warmed up and running in notch 8 should have a perfectly clear stack. If there’s any smoke, then something’s wrong. A properly operating GE will show just a hint of black under the same conditions.
The times I have seen the caption indicate that the engine was not pulling as well have been for photographs when the train appears to be running at speed.
Thanks for the advice everyone.
Gabe
The only locomotives that I see with excessive smoke here on Norfolk Southern, are old SD40’s & GP38’s. Guess they have not been used in a while?
White smoke is usually associated with burning engine oil. Not raw fuel. Raw fuel would be black in nature. Black smoke leaving the exhaust stack is just raw unburned fuel.
In the good ol’ days of late 50’searly 60’s white or buish white was “cold smoke” usually from start-up and trying to get going before it was fully warmed up. Black smoke on the other hand was from a throttle jockey going two or three notches past what was needed for acceleration. I love the smell of diesel smoke in the sunrise of early morning!
Since when… Please qualify the statement, white smoke is associated with lube oil .
ALL of the locomotives I had the pleasure of troubleshooting the lube oil will cover you in a slimy mess if you are standing anywhere near the engine. The sides of the carbody will be covered in oil.
Randy
These guys are right. white smoke=cold engine, or incomplete combustion. Blue smoke = lube oil, black smoke = fuel.
A sudden drop in load can cause a puff of black smoke if the fuel system doesn’t react quickly enough.
This is an interesting topic! From my experience in the diesel engine industry–from Cummins engine co–the reason a diesel pours out black smoke comes from one thing: overfueling the engine. This could have many causes—poorly calibrated injectors, delibrate overfueling to gain power, turbo lag, etc etc etc. But if you see black smoke—it’s too much fuel in the engine. As mentioned above, a properly calibrated diesel will show virtually no smoke at full load. The real danger of overfueling is the excess fuel washing past the rings and contaminating the oil. Not good!!!
Paul in Atlanta
years ago I owned a lobster boat (really!) with a nice normally aspirated Cummins diesel. Black smoke – I’d opened the throttle too fast; overfueling. White smoke (enough to cover a pretty good size harbour) – cold morning starting (and starting it with ether (he he he) made things much worse!
Electrical cabinet smoke is white also.
Randy
I realize I am missing something critical to my understanding of Mark’s response, but how does oil spewing everywhere relate to rebuilds?
A fresh coat of paint is often times enough to call a locomotive rebuilt. The lube oil running down the sides is a dead givaway to the extent of the rebuilding.
A real money maker if you can get away with it.!!!
Randy