Yeah, it’s kind of hard to get a 2 stroke engine to pass emissions. EMD did manage a tier 3 certification though. I seen a few prototype locomotives that had a 710-12 engine with the EGR system on them, but they were only rated at 3300HP. The railroad wasn’t really interested in those.
As far as 265H engine goes, EMD may have to go back to them. The SD90MAC’s they put those in originally were a pain to work on though.
Now, they have a rebuilt SD90 with a Cummins engine and 4200HP on tap to consider. We currently have a bunch of SD90’s that are sitting in storage that would be good candidates for this rebuild.