So on the route I've been working on, I have a small port with some siding tracks to deliver goods to and from each of the piers. However, due to the lack of company-owned real estate on the railroads part (or perhaps the poor shmucks who built the docks in the first place) the turning radius on most of the curves are tighter than most of the mainline locomotives can handle. Is there a way to generally restrict access to these locomotives to this area, while still allowing small switching locos to manage the area in at least some kind of prototypical fashion? Perhaps "Low curve Radii beyond this point" signage?