Low emissions switchers

[Rscott417]

It seems like a lot of railroads are ordering new or rebuilt low emissions locomotives these days. I'm curious to know, with the exception of the Atlas gensets, are there other variations of low emissions options out there either resin kits or 3d printed shells that could fit on existing frames? It seems if I want to model the present day these should be considered, and I kind of like how ugly they are. Here's a few examples.
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