Lee's response got me thinking more about trains in general and the sense memories connected to them.
For me, it's creosote and coal smoke: the smell of the Strasburg Railroad.
When I was a kid, my dad,
@EdKap2, being the consumate turn of the century PRR fan he is, made sure that we got out to Strasburg a couple times each year to see the 1223 and 7002 while they were in steam.
As a dumb kid, I always thought "The Big Engine" #90 was cooler. I can tell you, in retrospect and despite my continued love of that Baldwin decapod, he was right.
One of the things that still sticks with me after all of those years is the smell of the place: coal smoke, creosote and occasionally some hot grease.
Whenever I find that scent today I'm immediately taken back to those heady years of my youth when I did not fully appreciate the incredible thing I was witnessing.