Bowser HO Scale Union Pacific “Challenger” 4-6-6-4 Steam Locomotive – Kitbuilt Model. ? Product Overview A Bowser HO scale kitbuilt model of the Union Pacific “Challenger” 4-6-6-4 articulated steam locomotive, one of the most powerful steam engines ever built. This impressive model captures the might and presence of the legendary UP Challenger, a true icon of American railroading. Expertly constructed from the original Bowser kit, it’s ideal for collectors, display, or further detailing. Key Features? Bowser HO scale model of the Union Pacific “Challenger” 4-6-6-4? Kitbuilt and assembled from original Bowser metal and plastic components? Detailed boiler, cab, and tender construction with articulated drive? Realistic Union Pacific lettering and markings? Powerful locomotive design with twin-engine articulation? Compatible with all HO scale (1:87) model railway layouts? Ideal for display, restoration, or operational use (depending on condition)? If the item has its original box it will be shown in the photos. Mechanism untested; may require setup, lubrication, or minor adjustment before use. Please see photos for exact condition and detailing. Tender might be slightly different from Original.