From the rear grill, it looks like Scott used an OMI brass unit, but the handrails appear too thick for that.
It's a Kato SD40-2 snoot. The rear 3rd is scratchbuilt from styrene and Cannon & Co. HO scale grilles and Overland Corrugated grille material. It ends up being about 2ft shorter than a T-2, But it captures the look I think.