Overhang & Clearance: How Far Does My Car Swing on a Curve?

On a curve a long car doesn’t follow the rails neatly — its ends swing OUT past the railhead while its middle cuts IN toward the inside. Pick the car you run and your radius to see both, with a top-down view. Get it wrong and cars sideswipe scenery, structures, or a train on the next track.

The sliders only show you why — the verdict above is always the worst case. Slide the two cars until the inner car’s end lines up with the outer car’s middle to see the tightest spot.

Mid inswing = R − √(R² − (truck centers/2)²). End outswing is the car corner’s radial distance beyond the centerline. Adjacent-track need = car width + (end outswing + mid inswing). Geometry is a rigid-body approximation; real couplers and truck swing vary — confirm critical clearances by rolling your longest car through. Next, check the tightest curve a car tolerates in the Minimum Radius tool, or size your trains in Siding Capacity.