So I just bought the K4 (March Madness deal) and have been trying the Westward Wanderer scenario. I don't quite make it up to the curve when I get the 'loco out of water' message. I know I've been adding water to my boiler myself, which makes me question the 2nd loco...
I thought the last major core update we had fixed running out of water when doubleheading? Or does that only work with the automatic fireman enabled? Not that I ran steam before the update to know, I just came to Railworks a couple months ago and read that in the update list.
I suspected something was wrong with my installation, so verified the cache and cleared it multiple times (testing the scenario after each), same results. Then I enabled the auto fireman, and definitely made it a lot further with no problems.
Oh, the other thing I noticed with and without 'Otto'...when he was turned off, I was having a really tough time just getting up the hill, had to work the engine awfully hard for having 2 locos (wide open, barely holding 15-20 mph, and yes I managed to keep the boiler pressure just under 200 psi). With the auto fireman enabled, the consist flew up the mountain with power to spare. So I'm guessing control of the 2nd steam loco has something to do with the auto fireman also?