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Non turbocharged, works every time !
@mercer. There are two turbocharged units in this picture. Anything over 2000hp is normally turbo charged. The 2 trailing SD40-2′s have turbos.
Perhaps what you meant to say is no dynamic brakes on any of the units.
If airbrakes are used to slow or stop the train the chances of fires are increased.
Crazy crazy photo!
@engineered4u, what are you going on about? Bruce was obviously talking about the two lead units (4810-4798) which are not turbo charged. The SD40-2s in this shot aren’t even online. Sparks shooting out of the stacks of the GP38-2s are what caused the fire, not the air brakes. Perhaps what he meant to say was exactly what he said?
This train caused the fires? That seems like a pretty quick flare up considering the train hasn’t passed.
@Dave Brook, As I zoomed out and kept shooting, about 4.5 seconds later the fire had crossed those tier tracks and was at the fence line. Plus the two additional fires between where the train is in this shot and the area immediately parallel to me, plus the fact that dozens more fires followed this thing all the way to the next siding. It was the train.
@Tim..lighten up man. I am not a mind reader and when someone posts a shot with 4 units two of which are turbo charged and someone comments about non turbo charged units and I see two, I made the comment.
Sparks come out of many types of units my friend. I can’t comment what happens out West but here in Ontario and north, included in the TGBO’s and DOB’s it warns crews about fires starting because of braking.
Perhaps I meant exactly what I said?
I’m not sure why I need to lighten up. I didn’t think I said anything to offend you. However, if it’s not obvious that Mr. Mercer (perhaps has spent more of his life on a locomotive than anybody else on this site?) was talking about the non-turbo charged GP38-2s, then I think there are bigger issues here. Sigh… looks like we’ve hi-jacked the comment section of another photo again.
@Tim..agreed. This site should not be about anything other than the awe we feel about trains and railroading. You and I and Mr. Mercer have the privilege of working on a railroad, 36 years for myself.
I also find this site a great place to learn or share knowledge from photographers that were taking pictures when I was a kid. I find it fascinating to see some of these incredible images.
I am not an expert in all things railroading and have been proven wrong and thats ok as its all about learning.
That being said, I am more than happy to share any knowledge of being a locomotive engineer or railroading in general.
As for fires..well lets just say that I have caused a few myself (well my locomotives have) over the years.
Much respect Tim
Some may be interested in an explanation why non-turbo EMD engines have such hot (burning/sparking) exhaust. It is due to the 2-stroke cycle of their diesel engines. All of the exhaust (and intake) occurs in a VERY brief period near the bottom of the power stroke – for non-turbo the extremely hot exhaust blasts out the stacks immediately. Whereas for turbo engines, the exhaust path (through the turbo) is longer, so the exhaust has more time to burn off ahead of the stack.
In times past, CN equipped many of their GP9, SW1200rs, and GMD-1 locos with spark arrestors – which could still be helpful, but are pretty much history.
In comparison, Alco (MLW) and GE engines are 4-stroke cycle, having a separate exhaust stroke after the power stroke, resulting in less abrupt, less hot exhaust (when running properly – GE stack fires have happened).
Another 2-stroke diesel engine once used in some North American locomotives was the Fairbanks-Morse Opposed Piston engine.
Further to my previous comment, the risk of continuing combustion (sparks) in the exhaust plume is higher if it’s directly from the cylinders (non-turbo) and some or all cylinders of the engine are running rich (too much fuel versus air) – as suggested by the exhaust plume, looks darker than a well-tuned EMD engine.
The vegetation must have been extremely dry.
Apart from their less-abrupt 4-sroke exhaust, ALco and GE engines generally have the longer exhaust path of turbocharging (exceptions are some lower-power yard switchers).
I’ve seen turbocharged EMD and GE engines shoot flames out the stack a few times, the GE FDL engine in particular seems rather prone to puking oil into the exhaust manifold and then suffering a stack fire.
As with most diesel engine designs, 2 and 4-stroke alike, the non-turbocharged EMD engines will not completely burn their fuel and the piston rings will not seal as well when the engine is cold. This leads to a buildup of oily sludge in the exhaust manifold, which bakes into more sold carbon over time. A common way for this to occur is for the engine to be left idling for long periods, which of course is how locomotives spend much of their time. The technical term for this condition is “wet-stacking”.
When the engine is subsequently worked hard and heated up (like a yard engine getting out on the mainline) chunks of red-hot burning carbon buildup will be ejected from the stack, sometimes being thrown a considerable distance.
Turbo blades will usually chop up those carbon chunks into a finer dust (accompanied by a horrible grinding sound audible over the screaming roar of a 16-645E, and a large dark grey cloud), though I don’t imagine this is good for them.
Newer locomotive engines are far less prone to wet-stacking, due to the combination of turbocharging, computer-controlled electronic injection, and the AutoStart system, which greatly reduces the time spent idling.
I’m surprised to see those units out there, CN officially bans non-turbocharged EMD’s from road service in western Canada. We are also supposed to rev them up for 15 minutes at the start of a shift, or until the exhaust clears, to attempt to clear out the buildup before starting work.
If the exhaust manifolds are clean and the engine is worked hard, a non-turbocharged EMD shouldn’t smoke or spark any more than a turbocharged engine.
I really enjoy discussions like this, we really do have a unique job (I have about 10 years in on CN in Alberta, as a Cndr and Engr). One of these days I’ll have to splurge on a proper camera.
Apologies if this shows up as a duplicate comment, it didn’t appear to post properly the first time.
SD70Dude’s explanation of what is going on is great, makes so much sense that I wish I’d not commented before. Some burning carbon bits ejected from the stack must have been heavy enough to fall to the ground still incandescent.
As well as the GP38-2 being non-turbo, the 2-stroke engine-type could be a factor. A drawback of the two-stroke diesel is that it has to start exhausting before the bottom of the power stroke (simultaneously receiving air for the next cycle). So a bit less of the combustion energy transfers to the crank, while the exhaust will tend to be hotter and higher energy – great for igniting and blowing out carbon deposits.
The more participants in a discussion, the better. Everyone adds something different.
You are correct about the inherent efficiency loss present in the EMD 2-stroke design, which is not helped by the large amount of energy needed to run the roots blowers at high RPMs. Turbocharged engines recover most of that, and at full RPM the EMD turbo is 100% exhaust-driven, receiving no assist from the geartrain.
However, EMD engines of all designs should produce very little visible smoke when operating properly, due to the instant response of the gear-driven roots blowers or turbo that are found on all of them. Compare that to the smoke produced when a GE FDL or ALCO/MLW anything revs up.
Poor maintenance is a big factor in the amount of smoke and carbon buildup that is produced by these engines, CN’s yard engine fleet is quite worn out by now, having been ‘rode hard and put away wet’ for many years. Worn rings, pistons or cylinder liners allow lube oil into the combustion chamber, and damaged or stuck injectors will not properly atomize fuel or spray too much. Worn exhaust valves will not seat and seal properly, causing that cylinder to lose at least some compression and not burn properly.
Compare the exhaust of 4810 to that of 4798 in the photo. Based on that, I suspect it was the second unit that was starting the fires.
Lots of comments out there for sure.
All I know is that I loved the “turbo lag” produced when i was operating Alco/MLW products and having 5 SW1200RS’s or GP9u’s that has sat idling for hrs was always a most awesome exhaust show
@SD70Dude I believe your assessment that the 4798 was the likely cause is spot on.
I overheard the crew advising the train master that they had shut down the 4798 and started the 5276.
I also have enjoyed the mechanical assessment that you and jp4pix have provided.