Like many things involving operation of a steam locomotive, double heading is an acquired art form. As equally important as sharing the work, is realizing the that lead locomotive is setting the pace and the road engine is providing the "help". Handling a train where both engines are not near their tonnage limits is a lot more difficult than simply slugging it out with everything you've got up the hill. As Russ and Linn pointed out each engineer needs to think about how much tonnage is to be moved, how much his engine is capable of carrying, and run accordingly.
There were guys who were very good at this. There also were guys you let you do all the work if they could get away with it. After a couple of miles of hard slogging, I tell myself "to hell with this", and back off to what I felt we needed to pull. If the train slowed too much, I'd look back with a nasty look and sometimes the loafer behind would get the idea and dig in a bit.
Then there were was the guys who wanted to take the entire train up the hill themselves, and not allow me to do much. This was most annoying when I was running the helper for two reasons: 1. I didn't feel I was in complete control of the situation, with the road engine wailing away behind me. 2. Engine behind made more noise than my engine and I couldn't hear what my engine was doing. We'd get to Cumbres and my usual snarky comment to the guy behind was "well, you put on a good try, but I STLL beat you here by and engine length...."
Running fast up the hill is much more difficult for the fireman. 480's are not super power. Pushing them wide open up the hill at 15+ tends to run them out of water as the injector simply can't keep up at that pace. My worst firing trips were with some guy who thought he could get the whole works up the hill at 16 mph, throttle wide open (which is fine) and the Johnson bar dropped down where it should be with a full tonnage drag at 10mph (which is NOT fine). He did this regularly, ended up running both injectors all the time and laying his fireman's hide on the coal gate. As I methodically baled coal in with the injector wide open, I slowly watched the water creeping down in the glass. He looked over at the water glass, and bent over to prime his injector. I said "NO YOU DON'T......" I handed him the scoop and said, "you emptied it, YOU fill it up again." I must point out I was his boss and could pull rank like that. The poor abused shop guys who had to fire for him couldn't do that. I thought this course of action might make him see the light, but it didn't. He continued to hammer the engines up the hill.
I should point out the great video that Wacky Boy posted of 488 helping 463 up this hill shows great coordination between the two engines. In listening to them, both engines can be heard distinctly, they are doing it right.
Jim Pearce told me a great story about when he was firing out of Durango in the 1950's. There were two old head engineers, Squires and Buchannan, who were right next to each other on the seniority roster. They absolutely hated each other. They always seemed to paired up double heading out of Durango. One of them was always trying to mess with the other guy by letting him do all the work. One night they pulled into Gato for water. As a rather worn out Jim was on top of the tender filling it with water, the conductor came up to the head end. The frustrated engineer of the lead engineer told Al Lyons "Hey go back and collect a fare from old Squires. If he's not going to do any work, he needs to pay for his ride!"
