N GEN 4-8-8-4 Big Boy Locomotive with DCC & Sound, UP #4000 (ATHG-2253)

An HO-scale reproduction of Union Pacific's iconic Big Boy, the Athearn Genesis 4-8-8-4 Big Boy locomotive with DCC and sound (UP 4000) brings the power and detail of the prototype to your layout. This ready-to-run model pairs a heavy die-cast frame with a finely detailed boiler backhead, printed gauges, and individually applied piping, valves, and generators, while see-through running boards and cab windows add realism. Inside, a DCC decoder with SoundTraxx Tsunami2 provides authentic chuff, whistle, and bell sounds that operate in both DC and DCC, and a bidirectional LED headlight keeps illumination steady as it runs.

Designed to mirror the prototype, the Big Boy features the 4-8-8-4 wheel arrangement, large 68-inch drivers, and the kind of traction that made it famous. It ships fully assembled and ready to run, with body-mounted scale knuckle couplers, a heavy die-cast frame for traction, and a precise drivetrain for smooth operation at slow speeds. Road-number specifics like UP 4000 depict an as-delivered configuration with coal burners and cooling pipes; other finishes, including Primed for Grime and Legendary Liveries, let modelers tailor the look to their layout. It also supports MU lashups, full DCC control, and CV tuning, with a minimum curve radius of 11 inches to fit most HO layouts.