1203 is a C-C locomotive.
Also your right about weight on drivers. the 21 is perfectly capable of starting just about any train on the hill...and taking it up the hill. I think the biggest train we ever had behind it on a regular basis was 3 coach cars (Plume car, 3748, C&S 1116) and 3 White Pass Parlor cars. I'm not going to say 21 liked that train, but 1203 had killed itself, and we needed to keep the trains running. That only lasted about a week before 130 and 140 were leased, but it made it though without any problems. It moaned and groaned about it, but those traction motors are still under it 2 years later (granted I don't think we will ever top that train in regular service with the poor thing). The 21 is a damn reliable locomotive, it will do anything you ask of it.