Athearn No. 88676 is an HO scale Ready-to-Run model of Union Pacific No. 51, a General Electric U50 diesel locomotive. The model comes from Athearn’s original U50 production and represents one of the enormous 5,000-horsepower locomotives developed for Union Pacific during the horsepower race of the 1960s.
The original TrainReference photograph clearly shows Union Pacific road number 51 in the railroad’s yellow and gray paint scheme.
At a Glance
- Manufacturer: Athearn
- Product line: Ready-to-Run
- Item number: 88676
- Prototype: General Electric U50
- Railroad: Union Pacific
- Road number: 51
- Scale: HO
- Control: DCC-ready
Athearn 88676 Union Pacific No. 51
Athearn cataloged Union Pacific No. 51 as item 88676 in its HO Ready-to-Run U50 series. The model reproduces the unusual proportions of GE’s giant double-engine locomotive, including its long hood and distinctive span-bolster running gear.
This release belongs to the same generation of Athearn U50 models as Southern Pacific No. 9951, item 88679, also documented by TrainReference.
The General Electric U50
The U50 was developed in response to Union Pacific’s search for extremely high-horsepower locomotives during the early 1960s. Union Pacific asked GE, EMD and Alco for locomotive designs capable of helping the railroad assemble 15,000-horsepower motive-power consists.
GE’s answer was the U50. The locomotive was essentially built around two 2,500-horsepower diesel power plants on a common frame, giving it a total rating of 5,000 horsepower.
The U50 rode on four two-axle trucks arranged beneath span bolsters. This unusual running gear helped give the locomotive its enormous size and distinctive appearance.
Union Pacific’s U50 Fleet
Union Pacific was the principal buyer of the U50. The railroad ultimately owned 23 locomotives numbered 31 through 53.
The first three, Nos. 31–33, arrived in 1963. Additional locomotives followed during 1964 and 1965, bringing the fleet to 23 units.
Union Pacific No. 51, represented by the Athearn model, was part of the final group of U50s delivered in 1965.
Gas Turbine Running Gear
One of the U50’s most interesting features was its use of running gear derived from Union Pacific’s earlier gas-turbine locomotives.
The U50 fleet used reconditioned truck and bolster assemblies from retired Union Pacific 4,500-horsepower gas-turbine locomotives. The result was the characteristic arrangement of four two-axle trucks beneath two span bolsters rather than conventional four-axle locomotive trucks.
U50, Not U50D
These locomotives are sometimes identified in railroad books and model listings as U50D. The locomotive’s actual GE designation, however, was simply U50.
The U50D name came into use among rail enthusiasts as a way of distinguishing the original eight-axle U50 from the later six-axle U50C. For model identification, GE U50 is the more accurate designation.
Identifying Athearn No. 88676
The principal identifiers for this model are:
- Athearn item: 88676
- Locomotive: GE U50
- Railroad: Union Pacific
- Road number: 51
- Scale: HO
- Product line: Athearn Ready-to-Run
- Electronics: DCC-ready
Original Photo
The photograph below shows Athearn Union Pacific U50 No. 51 originally documented for TrainReference.
References and Further Reading
- UtahRails – Union Pacific Diesel Story, 1934–1982
- UtahRails – Union Pacific Diesel Locomotive Roster
Related Athearn References
Current Athearn U50 Listings
Current eBay listings related to Athearn U50 locomotives are shown below. For this particular model, look for Athearn item No. 88676 and Union Pacific road number 51.
As an eBay Partner, I may be compensated if you make a purchase.
 Athearn 88676 GE U50 Union Pacific (UP) #51 DC/DCC/Sound HO Scale |  Athearn RTR HO 91270 Union Pacific 50’ PD Youngstown #499202 |
