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Athearn Trains HO scale U50 diesel locomotive

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Athearn Trains HO scale U50 diesel locomotive
Athearn Trains HO scale U50 diesel locomotive
The Union Pacific RR is a pioneer in the use of high-horsepower diesel-electric locomotives, such as the General Electric U50 accurately modeled in HO scale by Athearn Trains. The direct-current model has a smooth-running mechanism that’s designed for the easy installation of a Digital Command Control (DCC) sound decoder and speakers.

The prototype. General Electric delivered 23 5,000-hp U50 diesel electric locomotives to the Union Pacific from 1963 to 1965. The locomotives were meant to serve UP’s requirement for a diesel-electric replacement for its gas-turbine-electric fleet. The Southern Pacific also purchased three U50 locomotives. General Electric reused the four-axle trucks on span bolsters from the UP’s 4,500 hp “Veranda” gas-turbines for the U50s.

The U50 was essentially two U25Bs put together. The locomotive had two FDL-16 2,500-hp 16-cylinder diesel engines. The front engine generated power for the two front trucks, and the rear engine powered the two rear trucks. Because of reliability issues, the UP retired all of its U50s by 1977.

Between 1969 and 1971, the UP purchased 40 U50C locomotives. Among other modifications, the U50Cs rode on six-axle trucks from retired 8,500 hp gas turbines. These locomotives were retired by 1978.
The roof features see-through walkways and grills and many separate details
The roof features see-through walkways and grills and many separate details.
The model. The Athearn U50 matches the dimensions of a diagram in the 1966 Car and Locomotive Cyclopedia of American Practice (Simmons-Boardman).

The plastic body shell has crisply molded equipment doors and other details. The walkways along the hoods have prototypical safety tread. The Athearn model features many separately applied parts, including scale profile hand rails, m.u. hoses, and ladders.

The U50 has separately applied radiator fans and see-through grills on the roof. Standout details are the equipment blowers behind the cab and at the rear of the hood. These are visible from the sides behind etched-metal screens. Just like on the prototype, you can see through the locomotive at these locations.
All the handrails mu hoses and the brakestand on the model are separately applied. The U50 also includes directional front and rear headlights
All the handrails, m.u. hoses, and the brakestand on the model are separately applied. The U50 also includes directional front and rear headlights.
The detailed cab interior includes separate engineer, fireman, and brakeman’s seats, as well as a control stand. Figures aren’t included. All windows have clear glazing, and the side cab windows have separate sun shades and wind deflectors.

The painting and lettering on the model match prototype photos. The Armour Yellow, Harbor Mist Gray, Aluminum, and Striping Red paint match official color drift cards from the UP. Printed General Electric builder’s plates are in the correct locations along the sills under the cab.

Athearn also sells an SP version that’s detailed to match that prototype.
The die-cast metal chassis provides much of the models weight
The die-cast metal chassis provides much of the model’s weight. The U50 can be converted to DCC by plugging an eight- or nine-pin decoder into the DCC socket. There are recesses in the chassis for two 1.2"-diameter speakers.
Mechanism. I removed four screws from the frame and lifted off the body shell. The locomotive pilots pivot, which is prototypical. The metal chassis, trucks, and mechanism are the same as the Athearn Veranda gas-turbine reviewed in the November 2010 Model Railroader.

The motor and flywheels are mounted in the center of the chassis. The two inboard trucks are geared to the motor, while the two outboard trucks are free-rolling. All the locomotive’s metal wheels pick up track power.

A printed-circuit (PC) board is mounted over the rear half of the chassis. A wiring harness attached to this PC board has a DCC socket that will accept an eight- or nine-pin DCC decoder. The factory-installed jumper board must be removed before decoder installation.

There is a 1.2"-diameter speaker opening with sound holes at each end of the frame. SoundTraxx ( sells a decoder and speaker kit for this locomotive. QSI Solutions ( is also offering its Titan stereo DCC sound decoder with appropriate U50 sounds.

The headlights in the model are 1.5 volt bulbs. However, Athearn has designed the lighting system so that you don’t need to install a resistor when converting the model to DCC.

The headlights turn on or off according to the model’s direction. There’s also a non-operating warning beacon on top of the cab roof.
Athearn HO scale GE U50
The model’s mechanism is quiet at all speeds. The U50 accelerated smoothly to a top speed of 75 scale mph. Depending on its gear ratio, the prototype could reach 70 or 80 mph.

The U50 ran on 18" radius curves, but it looks more realistic rounding broader curves. It also didn’t have any difficulty going forward or backward through a no. 6 turnout.
Price: $269.98

Athearn Trains
2883 E. Spring St., Suite 100
Long Beach, CA 90806

Road names: Union Pacific (four road numbers), Southern Pacific (three road numbers)

Era: 1963 to 1977 (Union Pacific)

  • All-wheel electrical pickup
  • DCC socket accepts eight- or nine-pin decoder
  • Five-pole skew-wound motor with dual brass flywheels
  • McHenry scale-sized operating knuckle couplers at correct height
  • Metal wheels in gauge
  • Minimum radius: 18"
  • Weight: 1 pound 11 ounces

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