dowlingm
Senior Member
For me the things which militates against rebuilds of locomotives and coaches are safety and accessibility - the VIA 92 crash pointed up the difference in cab safety standards between the F40s design period and now - and Metra has a lot of F40s. If the SD70MACs (now MACHs) have a cab which is reasonably current vs current FRA cab standards, then a Tier 3 rebuild is a reasonable choice which gets you most of the environmental benefit and retains the carbon previously expended in the frame, trucks etc.And you can find those who would say buying used locomotives instead of making new ones is a 'Green" option.
The calculations these days about what you "should" buy are quite politically complex.
It can't give you 80mph on the Oakville Sub, but that isn't what it was purchased for, so good luck to them.