I don't know why a K-28 is the question here. They have other engines they were and are running on the Cascade train. Most recently we have seen 481 and 482, plus before that 493. So if 493 is out of the rotation currently, that leaves just the 2 K-36's. So maybe they are keeping them for the passenger train. (1) Could be that a helper is needed, then both are required. (2) Could be if no helper is required they want a back-up engine. (3) Could be that they want to give the diesel a good workout (4) Could be they would prefer the diesel get the heavy work and spare the steam from danger. Not sure of the schedule, but this may be a day there are no passenger trains running at all, which is why they are doing the flanger train!!! Only the D&S knows why!!!!
Greg