[Animats]

> Sixty years ago refurbs would be much of the work going on at any large railway works - taking engines apart, stripping them down to the chassis and reassembling almost a new one in their place.

Here's the process.[1] This had to be done every 120,000 miles or so, which is every 1-2 years. On top of that, there's a few hours a day of routine daily maintenance.[2]

[1] https://www.youtube.com/watch?v=nZ3AN-kd66g