UP Challenger #3985 Weighs 487 Tons

Up close, trailing, and pacing! It’s all here!

While making a run through Fremont, Nebraska, this awesome machine shows the power associated with this type of articulated engine. An articulated engine is one built with the engine units that can move independent of the frame. Since the UP #3985 is so long, it would have difficulty taking normal curves without this feature.

Built specifically to take on long grades like her cousins the “Big Boys” 4-8-8-4’s, the #3985 Challenger was designed to pull freight fast up long grades without helper engines.

UP’s #4014 “Big Boy” 4-8-8-4, as wells as UP’s #3985 Challenger 4-6-6-4 are based at Union Pacific’s steam shop in Cheyenne, Wyoming.

Note: In the first 7 seconds, you can see the articulation of #3985 as she takes a small curve.

Some quick facts about the UP #3985 Challenger

• Builder – American Locomotive Works – 1943
• Wheel configuration – 4-6-6-4
• Locomotive and tender weight – 1,073,900 lbs
• Tractive effort – 97,350 lbf
• Nicknamed – Challenger

Let us know you like these massive giants of steam and would love to volunteer to help restore them in you could. We would love hear about it!