This is a Lionel 12031 Outer Passing Loop Track Pack. This set expands the basic oval of track included with Lionel starter sets into a larger oval with a siding. It creates a larger loop than the 12028 expansion pack. This track pack includes (5) 10 inch straight track sections, (2) O-36 curved track sections, (1) right hand switch with 1/4 O36 curve and (1) left hand switch with 1/4 O36 curve.