Consider using a mitre box to trim the occasional piece of track to close small gaps and fix overlaps. These typically occur around intersections and switches. Curve trimming is also necessary to achieve some of the more complicated and interesting custom layouts described in this guide.

Custom Track
You may also want to create your own special track sections. Examples might include a riser that curves to the left or right, 22½° curves, 30° curves, gradual ramps, spiral easement curves, angled crossing tracks, or a custom turntable. Rockler® sells router bits that facilitate making custom track pieces. You could also use these bits to create 2½" straight pieces from broken straight pieces on hand – something often needed to get lengths to come out right. You can also make additional crossing tracks from standard 4" straight tracks with a router. Shown on the facing page are a handful of ideas to get you started thinking.

Source for Custom Track
If you aren't prepared to fashion your own special tracks (maple, router, router bits, band-aids) MeskoToys™ in Michigan offers a wide range of custom tracks in their catalog.  If you don't see what you're looking for, they also create special pieces to your specification.  Visit their web site for a list of pieces available and layout ideas - www.meskotoys.com