I have an Epson Workforce WF2760 printer and recently tried (again) making yellow decals on clear decal paper. I’ve tried this a couple of times without success. The yellow just isn’t opaque enough. I did make yellow stripes on white decal paper and they came out fine. I could never vary the density of the yellow to be able to use the clear paper.
I would use white paper and make the background to match the black engine, or keep looking for decals.
I think I’m done kitbashing for Seaboard Air Line, decals are impossible to get. Try here, Jack has always come thru for me:
https://www.alleghenyscale.com/
Good luck!