My Grandfather was a rail engineer for 57 years and in fact he drove the Allegheny loco that now rests at the Ford. I can only imagine what that must have been like.
Oh wow! That thing is a beast! It's 125' long and roughly 16 1/2' tall. Whereas most locomotives have a big steam cylinder and piston with the piston rod running the drive wheels (on each side) thing thing is so long that it has two on each side (it's as if someone took two completely separate steam locomotives and bolted them together.) The drive wheels are articulated and have to be able to swing out from below the boilers -- otherwise the engine would derail trying to navigate curved sections of rail.
For those interested... here's a link: https://www.thehenryford.org …/alleghenyLocomotive.aspx
If you search, you can find some YouTube videos of some of these engines being operated. They are monsters. Your grandfather drove quite an amazing bit of engineering.