Vintage work crew photos

[Toolmaker51]

When start to think of them building that, one of the first thoughts is, how did they drill all those holes? Did they match drill them. Or were they that good they the parts could be pre-drilled, then assembled like that and the rivets still fit. Always amazing to see the old photos.

Very possible the holes weren't drilled, but punched. More rapid, better size control. Spacing not critical project to project, just that at hand. I'd guess plates were holed flat then rolled. Aren't boilers etc drilled on specific centers? The drum diameter and plate length adjusted to overlap X amount of times? If spacing correct, the lap absorbs extra material.
Hardest part might be jacking the ends closed.
But they did so; on a regular basis.