I can remember, in the 1950s, seeing wood burning trains come through town, belching out billows of smoke on their way.
Also, my generation, as very young children, remember the very tail end of ice boxes, and home coal delivery. Early morning milk delivery came in 1 quart glass bottles. The milk would freeze somewhat, pushing the cardboard cap up from the top, exposing the rich cream. We would then scoop that off and put it on top of our hot oatmeal. Pure delight!
the White Flags on the locomotives were a signal that they were pulling an Extra (unscheduled) train; most passenger trains & a few freight trains were scheduled, most freight trains had to have train orders to occupy the main line. Green flags (later lights) meant that there were following trains ('sections') of similar authority to be on the tracks; a train with following section blew the whistle to alert other trains in the area to clear a following section operating on the same schedule authority.
Steam locos were Extremely expensive to maintain, + the they required a wide variety of occupations/crafts for upkeep. Plus fueling & providing water (think water tanks all along the route) were cumbersome. Occasionally the boilers exploded due to neglect of pressures, water levels, etc.
When diesels came along late 40's / early 50's the end was near. Most Steam locos were scrapped but a few exist as museum curiosity exhibits around the world.