With respect to the Wreck of Old 97 - I agree that "Lost his airbrakes" is more likely than "Lost his average" - Trainmen do talk about "losing their air" in certain situations, although normally they have ways to recover it. The lyics were supposedly by a rairoad telegrapher who knew a little about Westinghouse train brake systems. Coming down a three mile grade an engineer trying to push the envelope could easily have made multiple brake applications and releases, without there being suffient time for the brake pressure to recover in between, resulting in what railroaders call "pissing away his air" - a situation where at a certain point the brake reservoir and brake lines no longer have enough air to permit a normal service application (or even to trigger the emergency reservoir, but I dont know if they had emergency reservoirs in 1903). "Lost his airbrakes" was probably more aceptable a lyric than "pissed away his air" and the writer may well have been trying to get across a concept that the public would understand rather than rely on technical railroad terminology in any event. Westinghouse patented the modern train airbrake in 1872 but it was not used universally in the US until 1900 when mandated by the federal Safety Appliance Act - and the systems were still pretty crude so as of 1903 many engineers were still not experts at all the ins and outs of what could go wrong with the systems .

Having his hand on the throttle is an interesting concept - as the throttle is a lever that stays put once you have set it - supposedly he did throw the engine into reverse, but that is done with a different lever. So what was he trying to do with the throttle - throttle up or down? At any rate a lot of engineers keep a hand on the throttle as a "default position" in case an adjustment is needed - you got to put your hand somewhere. Most engineers involved in accidents try to find some sort of position of safety - not that there really is one - like on the floor, or take some sort of protective position , in the final seconds when it becomes apparant that no further action can change the situation. This may well be a little poetic license. The newspaper articles of the wreck while pretty graphic about the scalded to death part do not mention the throttle bit. About the most specific description of body positions was the statement in the Raleigh News and Observer that "the bodies of all those killed were found in the wreckage of the different cars to which they belonged". The writer may well have just been trying to make "Steve" (actually JA Broady) seem particularly heroic by having him maintaining his post to the bitter end, like the captain of the titanic if was portrayed as having his hand still on the wheel

The song has plenty of factual inaccuracies that make for good drama - for example 90 miles an hour sounds a lot more exciting than the 30 to 35 mp reported by the eye witnesses.   Interestingly although half the crew was killed and nearly all the freight was demolished, 6 crates of canaries were unharmed.