PECO ST-21 Straight Track Addon Unit For Level Crossing Code 80 Setrack N Track. This unit is designed for level crossings and is part of the PECO Setrack N Code 80 system. The Setrack N Gauge Code 80 is a unit trackage system suitable for all popular brands of N gauge model trains. It is fully compatible with both Code 80 and Code 55 PECO Streamline, allowing for future layout development. The rails are made of solid nickel silver, moulded into sleeper bases for realism and strength. Turnouts are equipped with an over-centre spring for immediate use, eliminating the need for extra levers. The ST-21 unit easily clips onto the ST-20 to create a double track level crossing, and additional units can be used to cross multiple tracks.