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Original price $529.99 - Original price $529.99
Original price $529.99
$529.99 - $529.99
Current price $529.99

Athearn Genesis G1015 HO Scale 4-6-6-4 Challenger w/Coal Tender Union Pacific UP 3938 DC

ALCO constructed the first 4-6-6-4 locomotives in the world, numbered 3900 to 3914, for the Union Pacific Railroad in 1936. These huge engines were named the Challenger Simple Articulated, or CSA-1, class. The railroad received 25 near copies, classified as CSA-2, the following year.

Unlike compound Mallet engines that crawled along with drag freights, the Challengers had two sets of high- pressure cylinders and could safely reach passenger train speeds. The mammoth locomotives also had a heavy-duty starting tractive effort of 97,400 pounds.

Originally constructed to haul fast freight up the famous Wasatch grade, the CSA-1 and -2 Challengers would hold a variety of assignments over their long careers- including passenger service. Depending upon their operating territory, they burned either coal or oil, and some locos were converted back- and-forth several times.


  • Illuminated number boards and headlights
  • Headlight turns off in reverse
  • Illuminated directional back-up light in the tender
  • Correctly operating eccentric cranks
  • Adjustable top cab vent and cab windows
  • Pivoting front and rear engines for negotiating 18” radius curves
  • Current pick-up on all driver and wheels
  • Boiler backhead with full details and printed gauges
  • Synchronized chuff, whistle, bell, blow-down, air compressor, dyno and pop-off valve sounds
  • User-controlled whistle, short whistle, bell, squeal, coupler crash, injector, water stop and light dimmer
  • Individually-applied detail parts, including brass-painted bell and whistle, piping, valves, generator, steps, air pump, air tanks, reverser and coupler lift bar
  • Front coupler pocket can be inserted to mount operating coupler
  • Dual cube speakers for great sound quality
  • Upgraded headlight lighting with brighter LED
  • Improved loco-to-tender connection harness for increased durability and serviceability
  • Minimum recommended radius: 22”


  • DCC: Ready/21-Pin NEM
  • Lighted: LED
  • Sound: Ready
  • Minimum Radius: 22" (559 mm)
  • Reporting Mark: UP
  • Sub Brand: ATHEARN
  • Full Road Name: Union Pacific
  • Scale: HO
  • Wheel Configuration: 4-6-6-4
  • Era: 1911-1940
  • Prototype Manufacturer: American Locomotive Company (ALCO)