There's just something I find fascinating about old steam locomotives. I guess it's like what someone once said about how all the mechanical parts are outside to see in full motion. Those "Big Boys" where quite powerful right? I heard something like they could pull loads up to five miles long or whatnot.
The average train over the rough 1-2% grades of Sherman Hill, where the 4-8-8-4's were found most, wqs about 100-120 cars long. Tractive effort came in at about 135,000 pounds. They were capable of 80mph, but that was a safety factor. These in operation would have been limited to 50-70mph at most.
The end of the steam era came too early in the U.S., some of the N&W 2-8-8-2's built in the late 40's were as powerful as the Big Boy (though they were designed for slugging heavy coal drags of 100 cars in length in the Virginia's at 10-20mph usually, and then fast freights of 60-70 cars in length at 60mph), and had the C&O 2-6-6-6 Allegheny's been implemented properly, they could have exceeded their potential and enormous power of an estimated 7,500 drawbar horsepower (40mph), while the Big Boy at 40mph only produced 6,200 drawbar horsepower. Locomotives like the N&W Class J 4-8-4 were actually less expensive to maintain than diesels, and the 70" drivers they had were balanced well enough to hit 120mph. The engineering in the 40's was quite something.
The steam locomotive is the most beautiful, raw and vicious machine man has ever created. It leaves no secrets about it's power, and it can outperform what it's said to be capable of. They're almost alive, breathing, thundering beasts which I hope never leave this world. They may have been labeled as "obsolete", but they're capable of more than we think. Nothing is better than a steam locomotive running at full chat, or pounding up a mountain grade.