I can understand how matching two locomotives would not be hard. But doesn't the job become exponentially more difficult with a large number of locomotives? It seems the effort should increase by the square of number of locos.
No, it's linear. The "traditional" method is to start with one locomotive and match everything else to that, the newer and more precise method is to use a standard like the La Mesa 30/60 standard, and match everything to that. It takes 5-7 minutes per locomotive, and is fairly easy. If you want to really do it right, you would service, lubricate, and then warm up each locomotive first. People who do automated layouts with RR&Co have found that locomotive performance can change up to 10% as the locomotives warm up combined with fluctuations in room temperature.
Speed matching appears to be dynamic, not static and therefore is not a once and done thing. And that lies at the heart of RailPro's one undeniable advantage - a feedback loop and the necessary processing to dynamically act upon it.
It's an overly complicated method to avoid 5-7 minutes of speed matching per locomotive. It's one of those things that is kind of cool from a technology perspective, but is totally unnecessary in the real world. Doing the speed matching on straight, flat track gets it close enough for whatever scenario and allows you to calibrate it to a specific scale speed.
But for perfectionist buttwads like me, and more importantly, for sake of accuracy in the discussion I don't believe DCC speed matching with respect to consisting actually works. I think it is a case of close enough. In fact, the absence of a feedback loop in DCC makes it impossible to speed match under varying conditions. RP is effectively speed matching on-the-fly depending upon conditions. Bereft of feedback DCC can't possibly do that.
It works fine, the couplers hold together any slight differences in speed. Once you have a decent load behind the locomotives it ends up spread among the units anyway.
We tend to take speed matching for granted today, as it is quite simple to do, but it's one of the major features of DCC, and is generic enough in its implementation (other than differences between decoder brands) that it allows for different approaches to doing it, i.e. master locomotive, calibrated to a speedometer, and allows for having all locomotives on a layout speed matched, or different groups of locomotives matched to different speeds, i.e. switchers geared lower than road units so that any two switchers can be MU'ed, and any two road units MU'ed.
