Flaming exaust on GE & EMD Locomotives, Whats the Problem?

Question

I take photos as a hobbie, and I have seem many, older GE, and EMD locomotives with red hot flames, and with chocking black smoke shooting out of there exaust stack. I have ask this question to other rail fans but they can't explain why this happens. Turbo lag maybe? It's really neat to see at nite.

Answer 1

Andy F, I know all about those brake grids melting down!  I had one burn out one night that looked like the fourth of july had happened out in the middle of nowhere!  Blue flames, sparks, and a lot of smoke!  As to the flames, I agree with the other answers given here, and I had a turbo blow on me one night.  Flames were shooting 20 feet in the air, and got higher when I notched the power down on the unit!  That got me out of taking the train through to the coal mines!

Answer 2

The older GE's were noted for that, as were the old SD9s when under long, heavy load.  The flames would pulse cyclically, rising and falling in almost rhythmic fashion.

The EMDs are a different story, stemming from the way the turbo-charger operates.

The turbo's used on the GE four cycle engines are true turbo-chargers, running off the engine's exhaust, the same as any other turbo-charger.

But, the turbo-chargers on the two stroke EMD prime movers are actually a hybrid.  This design is gear driven up to and including throttle run #5 (slightly more than "half rack," referring to the rack fuel injection type system they employ), as is a "blower," then a clutch disengages the gear drive and allows it to operate as a turbo-charger, running off the exhaust.

Sometimes, when a clutch is failing, you'll hear a loud "bark" coming from the turbo-charger as the clutch slips (or gets overloaded) accompanied with very think, unburned carbon crud belching out of the exhaust stacks, which may or may not be accompanied by flame.

Also on older EMD prime movers, such as found on the aforementioned SD or GP 9s, their prime movers utilizing roots blowers, there are "carbon trap caps" that need to be cleaned periodically, to keep from building up soot and other combustables.  These are the most dangerous conditions, and different in that flaming debris is usually exhausted out the stacks in poor condition and can easily start a fire.

Of course turbo-chargers have been known to fail completely, resulting in explosion.  I have had one, but for a considerable period in the late 70's, on the Southern Pacific, messages were issued with train orders for crews going on duty that there was no one to be out on the catwalk on a GE locomotive under load.

They didn't have to tell ME but once...

Answer 3

I am willing to bet that you see it a lot more on the GEs than the EMDs.

There are a couple of things going on, here.  The first is a classical overfueling, due to a bad injector dumping in loads of fuel.  The EMDs use unit injectors, which are not as prone to this problem.

Another problem involves the turbocharger, which can go bad, allowing any number of spectacular events to occur.  Sometimes, on the 4-stroke engine, a bad turbo seal can cause an engine to burn its own lube oil, until it self-destructs from lack of lubrication.  Lots of black smoke there that you can't shut off with the EFCO button.

Answer 4

The railroad I work for has several older locomotives for use around the city where the main rail hub is located. Okay, they're really old - from the early 1950s. In certain situations we leave them overnight at a particular industry since we'll need them first thing in the morning to pull in 20, 40, maybe 60 loaded cars. In the winter, we leave them running all night so they don't freeze up. On these particular antiques, (SW 1200s) unburned diesel fuel will pool in the exhaust stacks and just sit there when the engine cools down from only idling. This doesn't happen every time, just sometimes. In the morning when the train gets going the few miles back to the switching yard, the engine is pulling pretty hard. The exhaust stacks heat up and ignite the unburned fuel. It's kind of embarrassing. But the only recommendation for it is to keep the RPMs up until the fire burns itself out.

Answer 5

Bob answered that pretty well.The only thing i can add is the newer G.E.'s seem to be cured of it.The Dash 8's were the last of the bad flame throwers. They seemed to do it worse if the throttle is advanced too fast.

Bob I hate when they start barking don't you?Sounds like a cat hacking up a fur ball. It really sucks when they decide to blow the turbo

Ziggie maybe you'll get lucky some night and get a pic of dynamic brake grids melting down on an older unit.Now that's really something to see!