"We used to sit out in the country and see the trains go by, watch the sparks come out of the smokestack. That was smokestack lightning."

Ewan Macoll's Dirty Old Town used the same imagery ."Saw a train set the night on fire"

"The word "stack" also calls to mind the American slang phrase
"blowing one's stack", meaning exploding in anger."

I like the way Hank Williams combined the image of the train's stack and his own stack in Rambling Man :
I can settle down and be doin' just fine
until I see an old train comin' down the line
I hurry straight on home to pack
And if I didn't go I believe I'd blow my stack