20 was assisting 40 climbing Cima Hill near MP 142 on August 31, 1943. 40's blind drivers dropped off on the inside of a curve and that was enough to pull the other drivers off and tip over the engine. She pulled the 20 over with her. Fireman Joe Wilmer on the 20 was trapped between a grabiron and a clinker hook and was pinned in the wreck. He was badly scalded and barely survived the trip into Durango where he died of his burns.
The wreck was also fatal for the 40 since her boiler was cracked on impact. In those days before proper welding was perfected this spelled the end. 20 lived on with a "new" cab and stack, becoming the jewel we remember from the mid and late 40s.