PECO SL-80 Crossing Single Slip (12 Deg.) Streamline OO/HO Track. Single slips were often used on double track lines to incorporate a trailing crossover into the access for a siding, goods yard etc. This trackage is suitable for mixing wheel standards on your 00/H0 layout. Code 100 rail allows flange depths up to 1.6mm which means that both vintage and current stock will run happily together. The wide range of turnouts and crossings in this series includes every type, and the geometry of this range has been cleverly designed to make it easy to build convenient, complex and aesthetically pleasing formations using combinations of small, medium and large radius turnouts.