In Lance Mindheim’s post this week about simple layouts, he likens himself to a dog with a tennis ball. He’s happy to repeat the same moves time and again, much like the professionals.
But what if you’re not like a dog chasing a tennis ball? How much complexity does it take so that you will remain entertained? Do you need a layout with ten turnouts or a hundred? When is more better, and when is it a waste?
It turns out to be a lower number than you might think. Consider car spots: they can each experience four actions – a car is dropped, picked, swapped or no change. So, in a single operating session, that spot provides four scenarios. With two spots, there are, however, not eight but sixteen scenarios because there are four possible actions for the second spot for each action in the first spot. It increases exponentially from there.
At seven spots, there are over 16 thousand possible scenarios, which is enough to last 44 years if you operated every day. At eight car spots, you might not repeat for 179 years, and by that time you’ll be hard pressed to remember the first scenario.
Now of course, not all scenarios may be equally probable, but in any case, the number of car spots required to seldom repeat an operating session is remarkable small.
Pembroke has eight car spots: team track, freight shed, retail coal, Pembroke Milling Co, stock pens, Lee Manufacturing coke, Lee Manufacturing platform, and engine coal. That should be plenty to keep me entertained for a couple of lifetimes, especially as, like Lance, I’m more like the dog with the tennis ball than I expected.
Pembroke:87 
I hear you panting and slobbering like a good Labrador…. Enjoy!