[herr_oberst]

Thank you for sharing those pictures. I love this site just for this kind of insight. All this technology hiding in plain sight.

Railroading stuff in general is fascinating. The engineering of many of the systems is very clever, and often 'simple in concept' (for instance the couplers), but obviously invented by mechanical geniuses.

I remember once reading about the interaction between the wheels and the railroad track. There's a hell of a lot more to that than meets the eye. Another simple idea - conical wheels - solving multiple problems: The opposing forces keep the train on the track, and the differing diameters through turns allow for differential action even though the wheels are on a common, solid axle.

There's a video on YouTube that shows the various systems in the BigBoy. Man o man. The linkage of the drivetrain, the engineering of the firebox, the path of the steam and the coal smoke....
All just engineering marvels.

Sorry for the tangent, JollyArmanto. My mind wandered looking at the pictures of the repairs of the rail cars.