Probably more than you’d think.
Track curvature is a major factor in determining if and where a site can be rail-served. If there’s not enough room to get the train onto the site safely, then it can’t be served.
Generally, an industrial track’s curve should be 12 degrees max. Worst case: If the track’s curve is too sharp, the train could fall off its tracks (aka derail). “Every now and then I fall apart…”
Total Eclipse of the Stadium:
Turn Radius of a Car, Truck, and Train
image courtesy of Norfolk Southern Industrial Development