Sorry Bob, but I gotta take issue with that. The size of a route has absolutely no impact on the performance of the route, and
performance is the point of the OP. Huge routes can be lo-impact and tiny routes can be slide-shows. Content is the sole issue that governs smoothness, size doesn't matter. The issue is how much content - and specifically how much
new content is in the present view. Trainz loads content into a cache till the amount of content equals the allocated space, then content needs to be dumped/loaded as the view changes. It's the dumping and loading that causes the stutters, which is why the crucial issue in route 'smoothness' is re-using content already present on the route and
not introducing 'new' stuff. An infinitely big route with no content change will run smooth as silk, a single board with excessive detail will stutter and jump....
Andy