N Challenger 4-6-6-4 Locomotive with Coal Tender and DCC & sound Black & Graphite, Clinchfield #670

Overview

Between 1936 and 1944, the American Locomotive Company (ALCO) constructed a total of 105 Challengers in five classes for the Union Pacific. These locomotives were approximately 122 ft (37 m) long and weighed 537 short tons (487 tonnes). While primarily used for freight service across the Union Pacific system, a few were also assigned to passenger trains like the Portland Rose. The design and operational experience of the Challengers played a crucial role in shaping the renowned Big Boy locomotive type, which, in turn, influenced the design of the last three orders of Challengers.

The Challengers boasted several technical breakthroughs that contributed to their success. Operating with a high boiler pressure of 280 lbf/in2, a feature typically reserved for passenger locomotives such as the FEF Series, they sported 69-inch drivers—impressive mammoth wheels typically found on passenger locomotives. Most freight engines required smaller wheels to generate the necessary torque. Surpassing speeds of 60 miles per hour, which was unprecedented for most other railroads using articulated steam locomotives, became a regular occurrence on the Union Pacific.

During Union Pacific's fourth order in 1943, ALCO built thirty-one locomotives adhering to the same specifications. However, due to the War Production Board's intervention, six completed locomotives were diverted to the Denver and Rio Grande Western Railroad through a lease facilitated by the War Department's Defense Plant Corporation. These locomotives, numbered 3900-3905, formed the Rio Grande's Class L-97. Later, in 1947, they were sold to the Clinchfield Railroad and renumbered as 670–675, becoming the Clinchfield's Class E-3. Unfortunately, these six Challengers were eventually retired in 1953.

Among the surviving Challengers, Union Pacific No. 3985 stands out. Restored by the Union Pacific in 1981, it operated in excursion service as part of the heritage fleet program. Recently, it was donated to the Railroading Heritage of Midwest America organization in 2022, where it is currently undergoing a second restoration. The only other surviving Challenger, UP No. 3977, is on display in North Platte, Nebraska.

Each model is equipped with Broadway Limited Imports' Paragon4 Sound/DC/DCC sound system, complete with smoke and integral GoPack capacitors.

Additionally, apart from the Paragon4 Sound/DC/DCC sound models, Broadway Limited Imports offers these locomotives as part of their Stealth series. These models, known as No-Sound / DCC-Ready, operate on DC straight out of the box. Alternatively, modelers can easily install their preferred DCC decoder. The front and rear lights are directional by default, and other lights are always illuminated with track power. However, certain lighting features may be dependent on the aftermarket decoder chosen by the modeler.

Features