Atlas O EMD GP7 diesel locomotive

Here’s a brand new model of Electro-Motive Division’s classic GP7 road switcher, and it’s a beauty. It combines the utilitarian look of the prototype with a powerful mechanism that’s suitable for nearly any assignment.

Manufactured by Atlas O, this well-detailed locomotive is offered ready-to-run with a factory-installed QSI sound decoder that operates on either DC or Digital Command Control (DCC). An unpowered version is also available.

The Electro-Motive Division’s 1,500-hp GP7 was introduced in late 1949 and built until 1954. The Atlas O model has perforated skirting above the fuel tank that identifies it as what railfans call a phase II version. A total of 2,729 GP7 diesels were built by the time the GP9 was introduced. The model matches prototype drawings in the Model Railroader Cyclopedia: Vol. 2, Diesel Locomotives.

Appearance. The GP7 follows the excellent plastic and die-cast metal construction we’ve seen in other recent Atlas O models. Its body shell has a one-piece hood with a cab and dynamic brake assembly that snap into place. Various combinations of small detail parts are individually applied to match each prototype paint scheme.

The radiator fans are well done and include movable blades within the fan housings. All of the railings are formed wire mounted on properly shaped metal stanchions that simulate the prototype’s bolted cast-steel fittings.

Painted crew figures are provided, but the view through the interior is masked to hide one of the motors. Both side windows operate and are fitted with wind deflectors. Sunshades are provided as user-applied parts.

The golden-white light-emitting-diode headlights automatically switch from dim to bright in the direction of travel. A pair of classification lights in the upper corners of each end change to display green in the forward direction, which is correct only for a scheduled train with a second section following behind it. The lights to the rear change to red as marker lights. The number boxes are lighted at both ends.

Our sample GP7 came factory-painted in the Maine Central’s Pine Green and Harvest Gold color scheme. Both colors were smoothly applied and all of the striping was perfectly aligned. The lettering was clearly printed and included appropriate EMD builder’s plates and ownership trust plates on the frame edges.

Mechanism. The GP7’s mechanism follows the same design Atlas O used on its previous GP9 (reviewed in the October 2005 MR). The chassis is die-cast metal, including the pilots and fuel tank, to give the unit a 4-pound, 2-ounce weight that helps it deliver plenty of tractive effort. All of the corner steps and footboards have fine see-through gratings, and the walkways and platforms include a realistic safety tread texture.

The rigid-frame GP (“Blomberg”) trucks have detailed die-cast metal sideframes with the early outside brake hangers and individually applied brake cylinders, piping, and swing hangers. The blackened nickel-silver RP-25 contour wheels match National Model Railroad Association standards.

Twin can motors fitted with brass flywheels power the locomotive. One motor is mounted vertically on each truck. All four axles are driven and all of the wheels pick up current. The DCC sound system and directional lighting components ride on printed-circuit boards mounted on top of the chassis. The hollow fuel tank contains a speaker for the sound system.

Dual-mode sound. The sound-equipped GP7 has a QSI Quantum sound system that offers plenty of volume and numerous specific sound choices. Dozens of adjustments are available to allow the user to choose and fine-tune whatever sounds he desires.

In DC the engine rpm sounds increased as I advanced the throttle. I also triggered the horn and bell using the power pack’s direction switch. Many of the sounds can be adjusted with the power pack as outlined in the instruction manual. The QSI Quantum Engineer analog controller (sold separately) makes accessing and programming sounds on a DC layout easier.

In DCC the decoder supports 13 functions, including the bell, horn, and coupler crash. Function 9 triggers the heavy load feature, which keeps the locomotive speed constant while you manually increase or decrease the rpm sounds using the throttle.

Operation. Using the factory default settings, our sample GP7 began moving steadily at less than one scale mph on DC or DCC. It continued to run smoothly and quietly throughout its speed range.
The dual-mode sound decoder uses quite a bit of current, so the DC top speed at 12 volts was only 32.7 scale mph. On DCC, the 83.9 scale mph is closer to the prototype Geep’s maximum operating speeds between 55 and 89 mph.

The dual motors produce a 17-ounce drawbar pull that’s equivalent to 52 free-rolling cars on straight and level track. However, the combined load of the sound system and two powerful motors draws nearly 4 amperes.

This O scale Geep is a superb model of Electro-Motive’s first road switcher. Its powerful mechanism and excellent finish make it an outstanding model.

Atlas O EMD GP7
Price: with dual-mode DCC sound system, $469.95; unpowered units, $209.95
Manufacturer
Atlas O LLC
378 Florence Ave.
Hillside, NJ 07205-1102
www.atlaso.com
Road names: (two road numbers) Atchison, Topeka & Santa Fe (silver zebra stripes); Lackawanna (black); Louisville & Nashville (black with cream); Maine Central (green); Pittsburgh & Lake Erie (NYC-style stripes); and Reading (black). Undecorated also available
Era: 1949 to present
Features
Twin can motors with flywheels
Dual-mode DC or DCC sound and control system
Eight-wheel drive and electrical pickup
Magnetic knuckle couplers mounted at the correct height
Minimum radius: 36″
Prototype-specific details
Weight: 4 pounds 2 ounces