I had kind of wondered how the loading worked. Would seem that if you normally have only one engine running with, say 500 available HP (after various parasitic loads like compressors and lights and the like), and ask for 1500 to shove a train, it's going to take some time to start up the other engine or 2 and bring the whole crowd on line. Maybe that's part of the problem - when the crew wants power they want it NOW, not in a few minutes after everything spins up. In that regard, the Green Goat hybrids might be better for yards if they would hold together - full power on demand from the battery, and the engine just keeps things charged.