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Union Pacific 9000

Southern California Chapter
Railway and Locomotive Historical Society

Union Pacific locomotive number 9000 was donated to the Chapter by the Union Pacific in May of 1956.  Designated a 4-12-2, or Union Pacific type, it is the largest steam locomotive built on a rigid frame and it has a wheelbase of over 30 feet.  Its 12 drive wheels are powered by three massive cylinders, one of which is located between the frame - transmitting its power through a crankshaft on the second driver axle.  The other two cylinders are connected to the conventional main and side rods which attach at the third driver.  Number 9000 was built for fast, heavy freight service and it is the only survivor of a group of 88 similar locomotives built for the Union Pacific.  It saw continuous service for almost 30 years and was used mainly between Green River, Wyoming and Council Bluffs, Iowa. 

Builder: ALCO Brooks Works Grate Area: 108.25 sq. ft.
Builder Type: 4-12-2S2495 Air Pumps (2): LT-6 8½" cross-compound
Construction No. 66544 Superheater: Elesco Type E
Erected: March 1926 Feedwater Heater: Worthington 5-SA*
Delivered: April 13, 1926 Throttle: Woodard balanced steam dome throttle valve*
Vacated: March 1956 Crank Angle ("quartering")
120° between all crank pins
Arrived in Pomona: May 3, 1956 Tender Class 18-C-1,  Vanderbilt waterbottom frame*
Drivers 67"*     Water Capacity: 18,000 gals.
Driver Wheelbase: 30' 8"     Coal Capacity: 44,000 lbs.
Tractive Effort: 96,650 lbs.

Adhesion Factor: 3.80 Locomotive Weight
Horsepower: 4,750 max. On Drivers: 367,500 lbs.
Fuel: Semi-bituminous coal Total: 495,000 lbs.
Boiler Pressure: 220 p.s.i. Tender Weight
Valve Gear: Gresley (Center) Light: 122,900 lbs.

Walschaert (Outside) Loaded: 310,500 lbs.
Cylinder Diameter: 27" Combined Loaded Weight: 805,500 lbs.
Stroke:  32" center*

  33" outside Total Length: 103'  1-5/8"
Stoker: Standard BK* Total Revenue Miles: 1,680,632


Shortening the piston stroke of the center cylinder by one inch (which connected to the second set of drivers) along with increasing the separation between drivers one and two (by almost 18"), increasing the separation between the first pair of drivers and the cylinder saddle and inclining the center piston assembly to an angle where the forward end was 9" above horizontal, allowed the center piston rod, wrist pin assembly and main rod to clear the first driver axle during all movement,  thereby avoiding the need to put a clearance bend or "crank" in the axle of the first driver set.

*Design Revisions
The original tender was a conventional-frame 15-C-1, holding 15,000 gallons of water and 22,000 pounds of coal.  This tender was wholly inadequate to supply the engine and was soon replaced with the cast waterbottom-framed 18-C.  Much later,  the road added coal boards around the bunker which allowed an additional 4,000 pounds of coal to be added, if and when needed.

The original integrated feedwater heater/pump assembly was the Worthington 4½ BL-2.  Changing to the 5-SA allowed the weight of the components to be distributed along the length of the locomotive and and not concentrated in one spot and on one side.

The 9000 retained its spoked drivers during most  its career.  However, Boxpok wheels were placed on the main driving axles (#2 and #3) on of many of the series.

Orders UP-3 through UP-5 received American Throttle Company's front end (superheater) throttles in place of the steam dome throttles on earlier Nines.

The 9000 was delivered with an Elvin Mechanical "paddle" Stoker, which also quickly proved to be inadequate.  Duplex D-3 tower stokers were applied to locomotives starting in the UP-3 order, but were noisy and took up significant space in the small cab.  Duplex D-1's gradually began replacing the D-3's. 

What's Happening

The Scoop

UP 9000 Photo Gallery

Union Pacific Collection

Chapter Collection

9000 gets some TLC

On display in Pomona

A shot of the UP 9000 in all its glory!!

Listen to a 9000

The following audio clips of UP-9009 were recorded by Howard Fogg in 1954 in Nebraska.

  9009 at a walk                               9009 going past a derailment                9009 at speed, whistling

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Page last revised - 07/01/2003 Facebook Page