Introduced: 2007 (first version) and 2024 (DCC-Sound version)
The first production run of these models was another typically fine looking and running Atlas diesel -
The mechanism sports all the features one normally associates with "modern" Atlas diesels - IE, split-frame / all-metal chassis, 5-pole / skew-wound "scale speed" motor, dual flywheels, low-friction drive, bi-directional "white" LED lighting, all-wheel drive and pickup (no traction tires), blackened / low-profile wheels, shell-mounted Accumate couplers, all-plastic gearing, etc. The chassis is fully DCC-Ready (and, in fact, available with factory-installed decoder). Other noteworthy features include operational low nose headlight (where appropriate), separate coupler cut levers, cab with 4 or 2 side windows (as appropriate per road name).
Performance on these first run models is perfect in every way - smooth, quiet, flawless pickup and throttle response, exceptional pulling power, etc.
Atlas released all-new U23B models in 2024. These were available either DCC-Ready or with factory-installed ESU LokSound decoders -
These models were redesigned along the lines of the Atlas Trainmaster re-release of the same year. Rather than using the old split-frame chassis to transfer current to the main PC board, the chassis is now essentially one big hunk of metal with wires from the trucks transferring current directly to the board. Additional wires from the board transfer current to the motor contacts. LEDs mounted to either end of the board provide directional lighting. The drivetrain components drop inside of the chassis and a separate metal lid screwed to the top holds everything in place. The main PC board is screwed to the top of the chassis lid. The main PC board comes with a preinstalled speaker on all models. The DCC interface (designed by ESU) is designated as "E24"
Everything else (trucks, shell, etc) look to be the basically same as on the previous version. It should be possible to swap shells between the two versions, although some modifications to the headlight shields may be required.
Performance on this new version is outstanding in every way and every bit the equal of the previous version. The only issue I ran into was a bit of "electric razor" noise in the mechanism, which I was able to mitigate by adding some lubrication to the bearing blocks.
Prototype information -
Powered by a V12 FDL prime mover, the 2250 h.p. U23B was GE's intermediate-sized four-axle road-switcher of the late 1960s through the mid 1970s. The U23B's direct competitor during this period was the very successful EMD GP38. In 10 years of production from 1968 through 1977 a total of 481 units were produced, making this the second best seller of GE's "Universal Series" locomotives. The first units were delivered to the Delaware & Hudson in August and September 1968. CSX predecessors Chesapeake & Ohio and Louisville & Nashville had a combined fleet of 120 units, giving CSX one of the larger active fleets in later years. Penn Central, Santa Fe and Missouri Pacific also purchased sizeable fleets of U23Bs.
Primary spotting features include a stepped-out radiator section and two sets of three tall engine access doors near the center of the long hood. During production, the U23B was equipped with various truck side frames, including Blomberg trucks from EMD trade-in locomotives, AAR-style trucks, or GE's own four-axle "FB2" truck. One of these three truck styles is included on our model where appropriate per road name.
Today the number of active U23B's has dwindled, but a handful can still be found working for short lines and regional railroads in North America.
Shell removal on these models is pretty simple. Just grab the fuel tank with one hand and the shell with the other. Then just sort of wiggle it up and off.
Grade: A
Reviewed: 07/07 Model Railroader ("Atlas has released a smooth-running and accurate N scale model of GE's U23B... The ready-to-run model has roadname-specific cab, headlight, and truck styles and is available in DC and DCC versions... The Atlas model is within scale inches of U23B prototype drawings... The body is made of three styrene castings: hood, cab and walkway. Separate factory-applied parts include the horn, railings, bell, exhaust stack, brake wheel, and plow. The thin-cross-section acetal plastic handrails and stanchions match the body color. As on the prototype, handrails at the step wells and the step edges are painted a contrasting color... paint was smoothly applied and includes impressively tiny pad-printed builder's plate and warning signs. The body is easily removed by grasping the long hood and gently wiggling the body back and forth to release the shell's cast-in lugs from the chassis. The split cast-alloy frame holds a 5-pole, skew-wound motor with two turned-brass flywheels. All four axles are powered, and all wheels pick up electricity. The wheels are blackened nickel-silver. All four wheelsets were in gauge. A top-mounted PC board includes to golden-white LEDs for directional headlights. The LEDs also illuminate the front and rear number boxes. Our DC sample took a bit of power; 3 volts, to get moving, but the mechanism was impressively quiet and smooth throughout its speed range. The model's minimum sustained speed was a silky-smooth 3 scale mph. Its top speed was 118 mph at 12 volts... There isn't much room for weight inside a narrow road switcher body. This 3-ounce model delivers a relatively modest .64 ounces of drawbar pull, which is below average but still works out to about 16 cars. The wheels are smoothly plated, and we've found that pulling performance often improves after the mirror-finish wears down a bit. The Atlas N scale U23B's nearly silent mechanism offers exceptionally smooth performance, and the accurate roadname-specific details should be please prototype modelers. $105 ($140 DCC)"