Athearn HO scale EMD GP7 diesel locomotive

The realistic rumble of a 567B diesel and an eye-catching paint scheme are but two of the highlights of this HO scale GP7 diesel-electric locomotive from Athearn Trains. Part of Athearn’s top-of-the-line Genesis series, the model features roadname-specific details and is available with a dual-mode SoundTraxx Digital Command Control (DCC) sound decoder.

The prototype. From October 1949 to April 1954 General Motors’ Electro-Motive Division built more than 2,600 GP7 diesel-electric locomotives for more than 70 North American railroads. The locomotive’s 16-cylinder 567B diesel engine produced 1,500 hp. In 1954 EMD replaced the GP7 with the 1,750 hp GP9.

The Atchison, Topeka & Santa Fe Ry. received 245 GP7 locomotives between September 1950 and December 1953. Of the 245 GP7s, 70 were delivered with dynamic brakes. The Santa Fe also ordered five GP7B units, which were the only cabless GP7s built by EMD.

The Santa Fe GP7 fleet had a long career hauling freight and passenger trains. Geeps used in passenger service were equipped with steam boilers to heat the trains. After being rebuilt in the 1970s, many SF Geeps ran on the railroad into the 1990s.

The model. Athearn revised the plastic body shell to address dimensional discrepancies found in the first release of the GP7 and GP9 models. (See my review of the Athearn GP9 in the
December 2011 Model Railroader). The height of the hood and the length and width of the cab windows, as well as the model’s other dimensions, match prototype drawings in the Model Railroader Cyclopedia: Vol. 2, Diesel Locomotives (Kalmbach Publishing Co., out of print).

Railfans refer to the locomotive that Athearn modeled as a phase II GP7. Spotting features for this production period (between March 1952 and December 1953) include fuel tank skirts with access slots and straight pilots. The model also has a 48″ dynamic brake fan that’s correct for a prototype built in July 1952 or later. The 82″ high engine access door just ahead of the dynamic brake blister matches the other doors along the hood and is correct for a GP7 built after March 1952.
 
Our review sample is decorated as Atchison, Topeka & Santa Fe no. 2855, which was built in July 1953. I couldn’t find a prototype photo of no. 2855, but I did find roster and assignment listings for it. I also referred to prototype photos of AT&SF GP7s from the same production group. The details on the model,
including the dynamic brake, are correct for no. 2855.

The model features a wealth of roadname specific details including cab sunshades, forward and rear facing horns, and a rooftop radio antenna and platform. All of the handrails are made of flexible acetal plastic. Other separate details include factory-installed wire grab irons and lift rings. Even the windshield wipers and m.u. hoses are separately applied painted parts.

The cooling fans on the long hood are especially impressive. These parts are painted silver under etched-metal grills.

The model is painted in the prototype’s as-delivered “zebra stripe” paint scheme. There’s sharp color separation between the black and silver stripes. The lettering placement matches prototype photos, including the KEEP OFF stencils on the pilots. Blue and red EMD builder’s plates are also printed on the sills under the cab.

Performance. The model uses the same mechanism as the previously reviewed Athearn Genesis GP9. The motor and flywheels are mounted in the center of a die-cast metal frame. The truck-mounted gearboxes transfer power to all axles and all the wheels pick up electricity from the track. There are additional metal weights above each gearbox.

I tested the model in DC with a Model Rectifier Tech 4 power pack. As with other sound-equipped models, the GP7 required a lot of voltage to get moving – 8 volts.

I enjoyed running the locomotive more with an NCE DCC system. After setting the decoder to 128 speed steps, the model crept along smoothly at under 1 scale mph in speed step 1.

The top speeds during both DC and DCC tests are close to those possible with prototype GP7 gear ratios.

Sound. The dual-mode DCC sound decoder produces some sound effects with a DC power pack. However, these effects are limited to the diesel rpms. A bell sounds when the model is run under 5 scale mph and a grade-crossing horn signal sounds when the direction switch is flipped.

The decoder has more user-triggered sound effects and programming options when it’s run with a DCC system or with a DC sound controller, such as the MRC Tech 6. Sound effects include a bell, long and short horn blasts, and the dynamic brake fan.

The diesel exhaust effect can be fine tuned in relation to the throttle speed step. I set the exhaust effect for manual notching by setting CV 116 to 0, CV39 to 64, and CV43 to 64. I could then
increase or decrease the rpms using function keys 5 and 9 regardless of the locomotive’s speed.

There are also CVs for adjusting individual effect volume levels and setting speed tables. An extensive SoundTraxx online user manual is available as a free download on the Athearn website.

Superdetailed out of the box, this Athearn model captures the sights and sounds of a workhorse Santa Fe GP7 of the 1950s.

Price: $179.98 (DC) $279.98 (DCC sound)

Manufacturer
Athearn Trains
2883 E. Spring St., Ste. 100
Long Beach, CA 90806
athearn.com
Road name (multiple road numbers: Atchison, Topeka & Santa Fe (freight or dual-service version available)

Era: 1953 to early 1960s (as detailed)

Features

• All-wheel drive and electrical pickup
• DCC Quick Plug (DC version)
• Dual-mode SoundTraxx Digital Command Control sound decoder (DCC version only)
• Five-pole skew-wound motor with brass flywheels
• McHenry operating knuckle couplers at correct height
• Minimum radius: 18″
• RP-25 contour metal wheels in gauge
• Weight: 111⁄2 ounces