| Union Pacific 3985 |
|---|
Union Pacific No. 3985 runs through Alton, Iowa, on October 1, 2008 |
| Type and origin |
|---|
| References: | | Power type | Steam |
|---|
| Builder | American Locomotive Company (ALCO) |
|---|
| Serial number | 70174 |
|---|
| Build date | July 1943 |
|---|
| Rebuild date | 1979–March 1981 (first restoration)
January 2023–ongoing (second restoration) |
|---|
|
| Specifications |
|---|
Configuration:
| |
|---|
| • Whyte | 4-6-6-4 |
|---|
| • UIC | (2′C) C2′ h4 |
|---|
| Gauge | 4 ft 8+1⁄2 in (1,435 mm) standard gauge |
|---|
| Driver dia. | 69 in (1,753 mm) |
|---|
| Wheelbase | 60 ft 4+1⁄2 in (18.402 m) Engine
121 ft 10+7⁄8 in (37.157 m) Engine + tender |
|---|
| Axle load | 67,333 lb (30,542 kilograms; 30.542 metric tons) |
|---|
| Adhesive weight | 404,000 lb (183,000 kg; 183 t) |
|---|
| Loco weight | 627,900 lb (284,800 kg) |
|---|
| Tender weight | 446,000 lb (202,000 kg) |
|---|
| Total weight | 1,073,900 lb (487,100 kg) |
|---|
| Fuel type | No. 5 fuel oil, originally coal |
|---|
| Fuel capacity | 32 short tons (29 t; 29 long tons)
6,450 US gal (24,400 L; 5,370 imp gal) |
|---|
| Water cap. | 25,000 US gal (95,000 L; 21,000 imp gal) |
|---|
| Firebox: | |
|---|
| • Grate area | 132 sq ft (12 m2) (grate removed in 1990) |
|---|
| Boiler | 94 in (2,400 mm) |
|---|
| Boiler pressure | 280 lbf/in2 (1.93 MPa) |
|---|
| Heating surface: | |
|---|
| • Firebox | 140 sq ft (13 m2) |
|---|
| • Tubes | 527 sq ft (49.0 m2) |
|---|
| • Flues | 3,687 sq ft (342.5 m2) |
|---|
| • Total surface | 4,795 sq ft (445.5 m2) |
|---|
Superheater:
| |
|---|
| • Type | Type E |
|---|
| • Heating area | 2,162 sq ft (200.9 m2) |
|---|
| Cylinders | Four |
|---|
| Cylinder size | 21 in × 32 in (533 mm × 813 mm) |
|---|
|
|
| Career |
|---|
| Operators | Union Pacific Railroad |
|---|
| Class | 4664-4 |
|---|
| Number in class | 11 of 25 |
|---|
| Numbers | - UP 3985
- UP 3967
- UP 3718
- CRR 676
|
|---|
| Nicknames | "The Challenger" |
|---|
| Delivered | 1943 |
|---|
| First run | 1943 (revenue service)
May 1981 (excursion service) |
|---|
| Last run | 1957 (revenue service)
October 14, 2010 (excursion service) |
|---|
| Retired | 1962 (revenue service)
January 2020 (excursion service) |
|---|
| Restored | March 1981 (first restoration) |
|---|
| Current owner | Railroading Heritage of Midwest America |
|---|
| Disposition | Undergoing restoration to operating condition |
|---|
|
Union Pacific 3985 is a four-cylinder articulated 4-6-6-4 "Challenger"-type steam locomotive built in July 1943 by the American Locomotive Company (ALCO) of Schenectady, New York, for the Union Pacific Railroad. No. 3985 is one of only two Challengers still in existence and the only one to have operated in excursion service.
No. 3985 operated in revenue service until 1957. It was then stored in the roundhouse in Cheyenne, Wyoming, until 1975, when it was placed outdoors beside the Cheyenne depot. In March 1981, after a group of Union Pacific employees restored the locomotive to operating condition, it was placed into excursion service as part of the Union Pacific's heritage fleet and became the world's largest operational steam locomotive. Mechanical problems took it offline in 2010, after which it was stored at the Union Pacific's Steam Shops in Cheyenne.
In May 2019, the title of largest operational steam locomotive passed to the newly restored 4-8-8-4 "Big Boy" Union Pacific 4014. No. 3985, still in poor mechanical condition, was retired from excursion service in January 2020. In April 2022, UP officials announced that the company would donate the locomotive to the Railroading Heritage of Midwest America (RRHMA), which is now restoring the locomotive to operating condition.
