Steam Locomotive Fans

Photo courtesy of Elliot Feinberg

Union Pacific #3985 is a 4-6-6-4 Challenger type locomotive. Currently, it is the largest operating steam locomotive in the world. It was built by ALCO in July of 1943 for it's one time owner, Union Pacific. It was restored by UP in 1981 for excursion service. 3985 is the largest operating steam locomotive in the world. It's truely a beast of a machine. It usually has to carry 2 auxilary water tenders behind it, because it consumes close to 200 gallons a mile!

Elliot Feinberg

Union Pacific ultimatly owned the largest number of Challengers, 105 out of the 200 built. The first of the 4-6-6-4s were numbered in the 3700 class. They were poweful performers, able to take a loaded freight up Sherman Hill unassisted (though the definition of "loaded freight" changed quite a bit when the 4-8-8-4 Big Boys arrived), although they had a problem with the front engine slipping. There was also a class of 3800's which shared many of the same chartacteristics as the 3700's, including the front engine slip. So when the 3900 class 4-6-6-4s were built, they made the front engine heavier by using heavier metals. The 3900s had a 280 psi boiler pressure, and could develope nearly 6,000 Horse Power. #3985 was one of the 3900s. She served the UP well until her riterment in 1958, pulling fast freights up Sherman Hill and east across the Nebraska plains. She recieved he last shopping in 1957 and was stored servicable until the Challengers were brought out in early '58 to help cope with rising traffic levels. More diesels arrived though, and 3985 was retired later that year.

3985 on display at the 2006 Super Bowl. Zach Pumphrey.

#3985 origonaly burned coal. It was converted to burn oil in 1990. This was accomplished by using the oil burner from UP Challenger #3977, on display at Cody Park, WY. Before it's conversion to oil, a fire crew had to follow 3985 to put out fires caused by sparks from the locomotive. The conversion took almost a year but when complete UP had a much more versitle engine that could be run easier and farther.

#3985 is currently undergoing light repairs in Cheyenne and is schedueled to run later this year.

Servicing 3985. Elliot Feinberg

3985 Specs:

Boiler Pressure: 280 pounds

Water: 25,000 gallons

Fuel: 5,945 gallons oil #5

Tractive Effort: 97,350 pounds

Modeling Tips:

Lionel proced an HO 4-6-6-4 in UP, D&RGW, and Clinchfield road names. Athearn also produces an HO Challenger in their Genesis line in the same road names. Various brass munufactueres produce Challengers. MTH and Lionel also make one in O scale, and I think either MTH or Aristo Craft makes a Challenger in G scale.