by: Frederick Boucher [ ]
Originally published on:
The Electro-Motive Division GP50 is the four-axle brother of EMD's "50 Series.” The 50 Series was an answer to increasing competition from GE Transportation Systems successful Dash 7 locomotives. With the fuel crisis of the 1970's, the Dash 7 series used a 12-cylinder prime mover instead of the standard 16-cylinder diesel. This used less fuel yet GE maintained the same power output. The GP50 (and six-axle SD50) used the 3,500 hp (2,600 kW) 16-cylinder EMD 645F3B diesel engine, an updated version of the 3,000 hp (2,240 kW) prime mover powering the thirsty SD40-2. Too much was placed on the engine and the 50 Series suffered relatively low reliability from failures of crankshafts and engines. The locomotive did boast a successful new anti-slip traction system. The successes and failures were lessons learned for the succeeding "60 Series.”
Two hundred seventy-eight examples of this locomotive were built by EMD between 1980 and 1985. A version of this locomotive called the GP50L was produced with an extended cab. The GP50 rides on the same frame as the EMD GP38, EMD GP38-2, EMD GP39, EMD GP39-2, EMD GP40 and EMD GP40-2, giving it an overall length of 59 feet 2 inches. 
Original owners were the Atchison, Topeka and Santa Fe Railway, Burlington Northern Railroad, Chicago and North Western Railway, Missouri Pacific Railroad, St. Louis – San Francisco Railway, Southern Railway (high hood units). They soldier on with Austin Western, Burlington Northern Santa Fe, Central Railroad of Indiana, Dakota & Iowa, First Union Rail, Florida Tri-Rail, Fort Worth and Western Railroad, and Union Pacific, et al.
Athearn's HO scale Ready To Roll series are fully assembled and ready to operate, and the GP50 is a sharp model. The GP50 continues the tried and true Athearn model engineering concept. You have an injection molded styrene shell set upon a die-cast underframe. It is secured by clips. Set in a depression in the middle of the underframe is their reliable skew-wound five pole electric motor with dual brass flywheels. This transmits power to both axles of each truck tower via pivoting driveshafts and worm gears, perfected through decades of Athearn locomotives. Power is conducted to the motor by the nickel plated, blackened machined wheels, thence via metal wipers. All eight wheels pick up power. None have traction tires.
The main body shell is molded as a one-piece hood and walkway with a separate cab, with an insert for the dynamic brake (or lack thereof). It is tightly secured to the frame with four clips that are accessible from the bottom of the fuel tank. Three configurations are available:
*GP50 Phase I
*GP50 Phase II
*GP50 without dynamic brakes
Athearn continues equipping their locomotives with plastic McHenry scale knuckle spring couplers. These are mounted to the frame.
The model is well protected in its packaging. It is securely held between two form fitted plastic cradles; thin cushioning sheets protect the top and bottom of detail parts from rubbing. The cradles are slid into a clear plastic sleeve, which is held in the sturdy two piece box. You can admire the model through the thin plastic window in the top lid.
My inspection finds the model to be in conformance with NMRA Standards and Recommended Practices with RP-25 wheels and couplers at the proper height. The model weights 14.2 ounces.
An exploded-view parts diagram is included. It gives no guidance how to disassemble or lubricate the model if need be. Also included is a small paper with instructions as how to contact Athearn.
detailsAthearn molding is sharp and crisp. The bottom steps are molded open. Fine wire grab irons adorn the shell, along with Celcon handrails, a horn, plow, step guards, and sunshades over the cab windows. All of these features are separately applied by the factory. This is a major improvement over Athearn's original "blue box" days of molded-on grab irons and metal handrails that you have to mount!
The windows are clear plastic. Further clear pieces are the front and rear number boards and headlights. These are illuminated via a bulb in the cab.
There is no interior cab detail.
The truck towers of B-B arraignment (a pair of powdered two axle trucks) have detailed plastic sidesframes representing Blomberg "M" trucks. Athearn details each side with a separately applied strut shock, brake cylinder, and swing hanger.
From coupler to coupler the model is 60 feet, a mere 1 percent longer than the prototype.
This model is Athearn's Ready To Roll basic line. Details and features not present on this model but found on Athearn's higher-end models are interior cab detail, sound, DCC or DCC-ready, MU connectors, and air hoses.
Livery and Markings
Athearn's painting of Central Railroad of Indiana No.5000 is incredible! A picture is worth a thousand words--notice the razor-sharp fidelity of the striping of CIND's livery. The paint is opaque yet does not obscure the wonderful detail. Athearn factory prints much of the stenciling found on the prototype. A superb finish.
This is a DC model. I tested it on Atlas code 83 track joined to a Peco code 80 slip switch, powered by a DC powerpack with an automatic pulse. Please see the video for two demonstrations.
The GP50 rolled smoothly and quietly over the track, quiet enough to hear the satisfying clickity-clack as the wheels passed over the frogs and points of the slip switch. This is quite pleasing as "blue box" Athearns were noisy, often referred to as "coffee grinders." At very low speed the loco slowed somewhat on the switch, but never did it stall. On tangent track the motor and drive are almost silent. I calculate the model can move at less than one scale MPH. Unfortunately, I was unable to test the model's pulling ability nor the electric draw of the motor; I never had to go above six notches on the powerpack, though.
This is a smartly engineered, beautifully decorated, smooth running model locomotive. Athearn lists the key features as:
* Fully assembled and ready for your layout
* Factory installed wire grab irons
* Factory installed Celcon handrails
* Super smooth drive train
* Nickel plated, blackened machined wheels
* McHenry scale knuckle spring couplers installed
Nitpick: photographs of CIND 5000 show the air horns mounted near the middle of the back of the hood, and a firecracker antenna over the cab. The horn throats are not molded open.
Athearn is a patriarch of the model railroad industry. Their old blue box RTR and kit trains are everywhere. Today the Athearn product line includes HO and N scale model railroad rolling stock and 1:50 (almost O scale, 1:48) die-cast vehicles. Athearn has also purchased Model Die Casting, upgrading those iconic models. While their Ready To Roll line is the basic product, the Athearn Genesis series are models of very high detail, featuring sound and DCC.
In 2004, Horizon Hobby, Inc. purchased Athearn and moved it into a state-of-the-art new facility in Carson, California. 
 Athearn website.
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