Orval Fairbairn wrote:

As I recall from 50-60 years ago, the steam trains burned high-sulfur,
"soft" coal, which put out quite a smell.

It depends on what part of the country you lived in, and what was
available.

The Delaware, Lackawanna and Western Railroad used to brag about how they
were the "Road of Anthracite." It was still high sulfur, so it had the
characteristic smell. They used a fictional character for advertising
called Phoebe Snow, who was dressed completely in white, to demonstrate the
cleanliness of hard coal. It still wasn't clean. The advertising campaigns
were the first to combine a fictional trade character with a jingle, like
th following:

==============
Says Phoebe Snow about to go
Upon a trip to Buffalo
My gown stays white from morn 'til night
Upon the road of anthracite.
==============