HO4-6-6-4 CSA-2 Challenger Locomotive UP #3938 (ATHG-1015)

HO-scale Union Pacific Challenger locomotive, road number 3938, is a detailed replica of ALCO’s CSA-2 class. This HO model captures the massive, articulated steam power of the Challengers and is designed for model railroad layouts to haul both fast freights and passenger trains with authentic presence on HO-scale tracks.

On the layout it features illuminated number boards and headlights, a headlight that switches off in reverse, and a tender back-up light, along with authentic detailing such as a full backhead with printed gauges, brass-painted bell and whistle, piping, steps and other individually applied parts. The design is built to negotiate 18-inch radius curves thanks to pivoting front and rear engines and to draw current from all wheels for steady power. For sound-equipped versions, a tender-mounted DCC decoder with SoundTraxx Tsunami2 sound drives the audio through dual cube speakers, with full DCC functions and compatibility in DC mode; CV changes let operators tailor performance, and a CV chart is included. The setup also features an upgraded loco-to-tender harness for durability and recommends a minimum 22-inch radius for smooth operation on typical HO layouts.