TdM #377, which started out as a class DL3 (a MLW RS-2) and was rebuilt to a RS-251, had a bad generator fire in 2002, and was shipped off to ILW for repair.

And there it sat until 2012, when it was plucked out of the deadline and rebuilt again. The damage from the generator fire was enough so the 251 couldn’t be reused (EPA emissions standards & the 251 do NOT go together), so instead the TdM shops bought a new Cummins QSK50 (Tier 3, upgraded later to Tier 4F) and rebuilt the locomotive with an long hood high enough to fit the taller engine + emissions control unit into, plus a rs-32-style cab and short hood instead of the turret cab hood it previously had.

Seven years later the Ann Arbor purchased controlling interest in the Great Lakes Central, pulled GLC (ex MSO, originally D&M) DL3 #466 out of the siding where it had been rotting for 9 years, and sent it to ILW for repairs. When it got there, it was discovered that the reason why the 244 didn’t turn over was because it had suffered freezing damage, had the block crack, and froze the crankshaft into place. So it too was remanufactured into a RS-250.

But in those seven years, ILW had done some instrumented testing of #377 and realized that with a little bit of extra venting they could squeeze a QSK-50 & exhaust scrubber into a only slightly raised RS-2 hood. #1339 (#466 was renumbered into the PV&T roster) came out of the shop with a little bump (DeWitt geep-style) over the engine block to accomodate the exhaust scrubber instead of the raised long hood that #377 ended up with.