Can someone explain something I saw today? A grain train was decending a fairly steep grade into town. The back DPU unit was a BNSF SD70 pumpkin. It was puffing huge clouds of black smoke in a chug-chug-chug pattern like a steam locomotive would. Any thoughts?
Turbocharger trouble, perhaps?
Certainly sounds like uncombusted fuel is being ejected from the stack. It could also be a stuck injector.
Could also still be “carboned-up” after sitting too long in the hole somewhere.
If you were getting distinct puffs of smoke, the engine wasn’t running very fast. I suspect that it was almost out of fuel (I’ve seen this happen after the fuel cutoff button was pushed). Your chugging was probably soon superseded by an alarm bell.
Any and all of the three posts above could explain the volume of black smoke. What about the fact that it was puffing out in a pattern like a steam engine? It looked like it was making smoke signals. I could make out the letters D…P…U…
It might also be dirty/plugged fuel filters. It won’t ring the alarm bell, but will cause surging and eratic or reduced loading.
It used to be one of Mr. Good Wrench’s (locomotive maintenance) favorite responses to engine problems. Second only to “Have you tried rebooting the computer?”
Jeff
They weren’t ALCO’s were they? ALCO’s were/are legendary as “honorary steam locomotives.”
Our RS18u’s look the same, but have different governors, one a Woodward, the other GE. The Woodward (as I recall) spools up smoothly, without a lot of smoke. Meanwhile the GE revs to the next notch quickly, getting ahead of the turbo with a characteristic blast of black smoke.