Atlas O 3-Rail 21st Century Track System(TM) track is designed to have the look of North American prototype trackage. Sections feature Code 148 solid nickel silver rail, blackened center rail, scale-sized ties with accurate tie plate, spike and bolt detail; a snap-lock system that securely holds the track sections together and ensures exact alignment and detailed rail joiners. The dark brown (or concrete-colored as specified) injection-molded tie strip has a special UV additive designed for both indoor and outdoor use. Flex-track is also part of the line offering you the opportunity for completely prototypical track planning. Perfect for use with all 3-rail O gauge trains.