Review

A pair of impressive new models of the Union Pacific Big Boy 4-8-8-4 are bying for our attention. Made by Athearn and Precision Craft Models, both models are excellent replicas of the world's biggest steam locomotive.

The two models include automatic dual-mode Digital Command Control and realistic sound systems that also operate on CD layouts.

The Athearn and Precision Craft Big Boys share a number of characteristics, starting with the chassis. Each locomotive has a pair of engines that swivel beneath the boiler and firebox. This compromise leaves a gap in the steam pipes above the rear cylinders, but it allows the models to negotiate curves as sharp as an 18-inch radius.

However, the Big Boys look much better on curves in the 30- to 36 inche range. On prototype articulateds, the rear engine was rigid and only the front engine moved from side to side on a hinge between the rear cylinders.

Athearn's model features a crisply detailed plastic boiler shell and cab that enclose a heavy die-cast metal chassis and mechanism. The model has excellent detail, with finely molded rivets, safety tread on the front platform, detailed cab and a see-through tread pattern in the running boards. Many individual details are factory-applied to produce an excellent freestanding appearance.

The mechanism is concealed inside the boiler. It has a powerful can motor and flywheels mounted in a heavy, two-piece die-cast metal weight. The model runs smoothly and quietly.

The model comes with a dual-mode sound decoder made for Athearn by Model Rectifier Corp. A push button radio control unit is supplied for use on DC, and it can be used to reset some CVs with your power pack. On DC, this unit controls the speed, direction, bell and whistle. During DCC operation, the function buttons on the throttle control the sound effects. A pair of downward-facing speakers are hidden in the tender, and the sound system's volume can be adjusted manually or through a CV. Overall, the sound effects are realistic.

Precision Craft/s Big Boy is made mostly of die-cast metal. Most of the model's 55-ounce weight is in the boiler, which consists of two well-detailed zinc alloy castings that join at the running boards. The cab is a separate casting. Numerous details are factory-applied to match specific prototype modifications made during the lifetime of the full-size locomotives.

A can motor and a pair of flywheels are mounted in the middle of the boiler. The model includes a smoke unit that can be turned on or off. It delivers a realistic plume of smoke during operation. The model is a smooth, quiet runner.

The Big Boy included an automatic dual-mode DDC decoder and the Electronic Solutions Ulm LokSoung sound system concealed within the tender (the model is also available without sound and DCC). Dual 1-inch speakers are mounted face down on the tender floor. A DC Master control unit, sold separately, allows users to operate sound effects during DC operation. In DCC operation the sound effects are controlled by the function buttons on the throttle, and the sound quality is good.

Both models reflect the top quality design and construction techniques favored by their respective manufacturers. Both locomotives can haul 125-car consists that'll be impressive on any layout, and both will operate well on curves down to a 22-inch radius.