1203 is actually a fairly neat locomotive. Its got far more then 13k, try closer to 19k. But being a diesel, that does not limit it like steam does, It could likely move a train at least as big as a K-28 can. I'd be shocked if it was hard on track, it has less axle loading then literally anything at the D&S, 80 tons spread across 6 axles. Remember a loaded K-36 is over 100 tons. Its got an ALCO 251B prime mover.
It worked great at the Loop, but the long rigid wheel base was its downfall. It was too big for a 30 degree curve, it would do it, but it took a toll on track an flanges. It had no issue hauling a full, 9 car train up the hill....we start on a 3% grade under the bridge, its flat in durango by comparison. I always felt it could easily haul about 15 cars.
Durango is much more suited to 1203, no sharp curves, long stretches, speeds around 20 MPH, exactly what it was built for. The Loops speed is around 10, the engine was geared for 20-30 MPH or greater.
As someone who has fond memories of that engine (along with a lot of not so fond ones) I would gladly ride behind her in Durango, see what she can do on a railroad more like what she was built for, watch her stretch her legs. And listen to that ALCO glug its way up the hill. People say diesels don't have personalities, but they do, and 1203 had a very unique one, to say the least. She loved to surprise you, in good ways, and bad. But in the end, she really is a sweet machine. And I hope she enjoys her new home. We miss her here at the loop (sometimes). But we have her sisters to keep us company.