LEGO 4515 Straight Rails is a Trains 9V set released in 1991, containing 8 pieces. It provides eight straight 9V track sections intended to expand layouts for the LEGO 9V train system. The tracks are compatible with later Remote Control Trains, allowing mixed layouts with electric and battery-powered rolling stock. This pack was also bundled in product collections including 65801 Trains Value Pack, 65537 Classic Freight Train, and K2159 Holiday Train Starter Collection.