I have read enough real stories to realize that depending on the engineer, hand firing could be real work. Kind of like shoveling ear corn into the sheller but a lot longer.
Absolutely yes, the Engineer can, and will, teach a new Fireman a real lesson. When I was learning to fire on the Buffalo Creek & Gauley RR in 1962/1963, I really thought I was getting better and better. Finally, the day came when I was to "fire on my own" with the regular Fireman simply riding the seat-box. I was doing pretty well, just as I was taught, firing the "horseshoe pattern", then resting awhile, then shoveling again. After the stop for water at Swandale, the ascending grade got steeper, for the final 8/9 miles up to the coal mile town of Widen, West Virginia. The further we went the more I had to shovel, eventually shoveling continuously, without a rest.
The next day, Hosteler Bob Curthers asked me how everything went. I told him everything. I smiled, and said, "How did the engine sound?", and I responded that she really sounded great, nice and loud! Bob smiled again and said, "No, I mean REALLY, how did the engine SOUND?". I said that I didn't understand what he meant. Bob then went on to explain valve gear cut-off, and how the Engine could work a Fireman to death by keeping the power reverse gear way too far in the corner, thus wasting water and fuel. Bob then handed me a small piece of welders soap stone, and explained that when the big 2-8-0 sounds nice and sharp, and I'm able to follow the "normal" firing pattern, with rests, then note where the Engineer has the reverse gear set. Reach over his lap, and make THAT SPOT with your piece of soap stone.
Sure enough, after the water stop, I began to shovel harder and harder, and harder! I then remembered that I had used the soap stone to make the power reverse quadrant, when the exhaust sounded nice and sharp, and I was firing easy. Well I'll be darned! Engineer Jobe Young had the power reverse gear WAY FORWARD of my mark!!!! I reached over, tapped Mr. Young on the shoulder, and pointed to my mark on the reverse quadrant. He smiled broadly, took his pipe out of his mouth and said, ""You're learning kid!", and promptly hooked her up where she was supposed to be. I've been learning about steam locomotive operations ever since.