I have been reading through magazines as well as searching the threads and posts and there is one aspect of operations that I have found nothing definitive on. In many discussions about operating sessions they talk about scale time where an operation that would take X# of minutes or hours on a prototype is allowed a shorter time on the model. My question is, is there a formula for determining this ratio or is it just an arbitrary approximation? Also, are there different ratios for different scales (N vs HO)? If it is arbitrary, is there some way to make up a workable schedule? No wonder we can't get those LPBs to do any work.