Lately, I've been pondering the number and size of industries / customers on medium-sized switching layouts.
There are proto examples for both, but what do you think "works" better - several small industries so you can switch a variety of cars or fewer (maybe just one) large industry or customer? I don't think there's a right or wrong answer, just curious what other people think.
There is that word again, "better". Works better for what, visual effect, efficiency, operational interest, mix of car type, or?
Car type depends on the industry not just the size. An oil company is going to be limited to tank & box, while a fuel company would had hoppers to the mix.
A packing plant only has basically reefers and box, but there is a lot of work to do with those few cars. Spotting the in coming cattle, moving the cars to clean out, putting the reefers to sanitize, running them to ice, etc.
A large customer like a steel plant will really provide a big mix of car type and specialty cars in addition to a large amount of internal switching work. It would be easy to have a whole layout of just a steel mill.
Many small customers provides some switching puzzles for operation. Say a car gets spotted and the customer begins unloading. Suddenly that car can't be moved until they are done. Other cars "behind" it on the spur must be taken out the other side or through an escape track.
And what about that small customer that gets cars that can only be unloaded through one door. They only have a 1 sided dock so the car has to be turned so the correct door is facing the doc.