GP38-2 Phase 1 -
GP39-2 Phase 1 -
GP39-2 Phase 2 -
Introduced: 1996 (GP40), 1997 (GP40-2), 2001 (GP38), 2002 ("Early" GP38), 2003 (Revised GP40-2), 2004 (Revised GP40), 2007 (GP38-2), 2018 (DCC-Sound versions and GP39-2 Ph 1) and 2020 (GP39-2 Ph 2)
These models all share the same basic internals (not to mention their external similarities), so to save myself a bit of time I'm going to cover them all here. However, one note before we get started - Atlas also imported a really terrible GP40 model back in the late 60s / early 70s (manufactured by Mehano/Yugoslavia). Do not confuse that piece of junk with any of the Chinese-manufactured models on this page (it is covered elsewhere in this encyclopedia).
The first in the line, Atlas's 1996 GP40 model, was the only one of the bunch to not feature a DCC-Ready chassis -
The mechanism sports virtually all the other features one normally associates with "modern" Atlas diesels - IE, split-frame / all-metal chassis, 5-pole / skew-wound motor with dual flywheels, low-friction drive, bi-directional LED lighting, all-wheel drive and pickup (no traction tires), blackened / low-profile wheels, shell-mounted couplers (Rapidos), all-plastic gearing, etc.
The 1997 GP40-2 release was Atlas's first DCC-Ready model (the original GP40 chassis having been modified slightly, allowing for the installation of a full-length lightboard with motor contacts). These models were actually available with factory-installed Lenz decoders (the first USA profile model since Arnold's 1991 Alco S-2 to be so equipped). This same basic chassis/mechanism would be used for all the rest of the models in this series up until 2018 (when the internals were completely redesigned) -
The 2001 GP38 release (pictured at the top of the page) introduced a few new features into the line - painted handrails, Accumate couplers and Atlas's new "scale speed" motor. An "early prototype" GP38 was released in September of 2002 -
The 2003 GP40-2 release improved upon the original by including painted handrails, Accumate couplers, scale-speed motor, "golden white" LEDs, and "improved" roof detail (whatever that might have been). The first DCC-Ready GP40 came out in 2004, sporting all of the features of the previous year's GP40-2 models. An all-new GP38-2 model came out in 2007 (again, all the same features as previously noted).
The shells on all of these models are quite similar in size and shape, with the actual differences boiling down to minor variations in detailing (as driven by the actual differences between the various prototypes). But honestly, unless you're a seasoned locomotive spotter, the differences between, say, a GP40 and a GP40-2 are going to be fairly minimal and difficult to detect. These early releases are all exceptional models - crisp paint, fine detailing, smooth and quiet running, nimble throttle response, reliable pickup, decent pulling power, etc.
Having said that, it should be noted that every once in a while one might encounter one of these early models that seems to make a bit more noise than it should (usually showing up as squealing/screeching sounds, particularly through curves). If the model was built before 2016, a suggested solution to this problem (pioneered by the inestimable Ron Bearden) is to remove the inner bearing blocks and slide the hex nuts further into the flywheels -
Stock configuration -
Circa 2016, Atlas revised the internals on these models slightly (presumably to address whatever design problem was leading to the aforementioned noise issues). As pictured below, the hex nuts on the flywheel end of the worm shafts were removed and replaced instead with U-joint connectors -
In 2018, Atlas released revised versions of these models (along with an all-new GP39-2 model). As pictured below, the internals were completely redesigned to include support for an ESU LokSound DCC-Sound decoder and accompanying speaker (analog versions and non-sound DCC versions were also part of this release). Instead of using screws and hex nuts to hold the chassis halves together, this new version uses plastic clips on either end of the chassis (the fuel tank and motor saddle also contribute to holding things together) -
Gone are the chassis contact strips that the truck axle-wipers used to rub up against (an Atlas staple since the 1980's). Instead, small wires are soldered to the axle-wipers on the one end and to cylindrical metal plugs (which press-fit into holes in the chassis) on the other. Said plugs are extremely tight fitting and I couldn't get them to budge using even a moderate amount of pulling force (I spared the elbow grease because I didn't want to risk damaging them by really forcing the issue). I guess the safest way to do it is to disassemble the chassis and push the plugs out from the inside. Each plug has an open seam (lengthwise), so I suppose it's possible to resize them should they wind up getting too loose.
The rest of the internals are more or less the same as before. A five-pole / skew-wound motor spins dual flywheels. In turn, the flywheels spin plastic shafts with notched-cups on the worm side. Said cups spin little ball-and-pin connectors on the wormshafts. Bearing blocks inside of notches in the chassis hold the brass worms in place.
A long plastic shield is clipped to the top of the chassis (dunno why - but maybe to prevent short circuits between the decoder and chassis?)
I particularly like the way the circuit boards (and contacts thereto) have been redesigned. Very similar to IMRC's SD40-2 of 2017, metal contacts on the motor saddle transfer current from the main PC board (or decoder) to the motor and to the speaker mounted inside the fuel tank (note that even the non-sound locos come with a speaker). Unlike previous Atlas locos, the main PC board slides in and out of its chassis slots without the need to partially disassemble the chassis first (a nicety that Kato has offered for years). The design and placement of the new PC board contacts is also an improvement over previous Atlas diesels (where getting the motor contacts to line up with the contact pads on the PC board was admittedly a bit "hit and miss").
All eight wheels provide pickup, all four axles are geared, and all gearing is plastic. The wheels are blackened and low-profile. The trucks and fuel tank appear to be the same as on previous versions (in fact, the fuel tank still bears its "1996" copyright stamp). Note that speaker holes in the fuel tank are not provided (and not really required since the speaker is positioned such that sound projects upward rather than downward).
The shell is all plastic and includes separate detail parts for the windows, numberboards, handrails, sidesills, plow, roof vent, and horn. Couplers are shell-mounted Accumates. According to Atlas, shells from previous releases should work just fine with the newer chassis.
Performance on this new version is basically the same as its predecessors (IE, excellent). Out of the box, I didn't have any problems with the wheel-blackening causing any sort of jitteriness. They run very quietly, throttle response is smooth, pickup is flawless, slow speed creep is "one-time-at-a-time" and the top-end speed is realistic (IE, not too fast). No problems with any of the wheels derailing (even on 9.75" radius curves). Pulling power is decent (albeit unspectaclar), with mine able to handle around 23-24 assorted 50' freight cars through curves on level track. I didn't notice any difference in performance when operating mine with an analog powerpack (IE, they run equally well using DCC or DC control). Overall, these are superb looking models that run admirably well.
The sound on the DCC-Sound versions is well rendered, although I will say that the noise generated by this particular prototype has a bit of a high pitched whine to it that I find annoying. On the plus side, the default settings for speaker volume are not set obnoxiously high.
As seems to be typical with DCC-Sound models these days, the decoders in these locos are programmed to go through a rather protracted sequence of "start up" shenanigans before the loco will start moving (and with similar behavior when slowing down). To eliminate this nonsense (if you're so inclined), simply set CV124 to 0. Also note that the default behavior is for the sound to be off (IE, put the loco on the rails and it won't make a peep). To turn sound on, hit F8.
(Thanks for the pictures, Ron)
Trivia - Life-Like/Walthers GP38-2 shells will fit on this Atlas chassis, although not vice versa.
More Trivia - Briggs Models makes a number of different GP40-2L shell kits that can be powered using this Atlas chassis (a Life-Like/Walthers GP38-2 chassis will work as well) -
Still more trivia - ICG/IC fans can make an SD28 stand-in by mounting an Atlas GP38 shell and SD35 walkway on an SD35 mechanism (note that it may be necessary to file a small amount of metal off the ends of the frame to get a good fit). Not 100% accurate, but it does capture the overall look of a normally aspirated SD35 quite well -
Shell removal on these models is pretty simple, just take hold of the fuel tank with one hand and the shell with the other, then just sort of wiggle it up and off.
Grade: A (for all of 'em)
First GP40 eviewed: 5/97 Model Railroader ("Atlas has continued the trend of offering high-quality locomotives with its latest offering, a fine model of an EMD GP40. The model runs smoothly and its nice detail is accented by great lettering. Atlas' N scale model nicely captures the lines and proportions of the prototype. The moldwork is sharp and the model's dimensions match EMD specs. On our samples, which were lettered for three railroads, the paint was even and the lettering was very sharp and readable - even down to the subclass lettering under the cab! The only flaw I noticed was a little fuzziness in the separation line between the green and yellow on the C&NW unit. But even that disappears at typical viewing distance. The factory-applied number boards are a nice touch. The models follow standard N scale locomotive construction: an injection-molded shell riding on a split-frame chassis that surrounds the skew-wound five-pole motor. All wheels pick up electricity and all four axles are powered. I couldn't be more pleased with the performance of this model. Right out of the box it started smoothly and ran quietly. This is the second Atlas locomotive made in China (previous N scale Atlas engines were made by Kato) and I'm pleased to report the quality control problems encountered on some of the earlier GP9s have apparantly been corrected. All three of our locomotives performed extremely well. Noise was minimal, although the model was noticeably louder at higher speeds than my Atlas Kato-built GP35. I was quite impressed by the engine's slow speed right out of the box, as it crept along at less than scale 3 MPH... The drawbar pull of .8 ounces equates to about 20 typical N scale cars... Atlas is to be commended for the job they've done with this locomotive. The GP40 is a fine model that will find a home on many N scale layouts set between the mid-1960s and the present. Undec, BN, Chessie, C&NW, CN, CB, Conrail, CB&Q, D&RGW, L&N, MKT, NYC, UP. Price: $84.95")
GP40-2 reviewed: 1/98 Model Railroader ("Modelers using DCC should be ecstatic with Atlas' decision to offer its new model of an EMD GP40-2 with the option of a factory-installed Digitrax Command Control decoder. Non-DCC users will also be pleased, as the smooth-running model features nice detail... Since the prototype GP40-2 had the same frame dimensions as the GP40, Atlas used the same drive and mechanism as its excellent GP40. Like the GP40, the Dash 2 is available with or without a dynamic brake blister atop the hood. The blister is the standard dynamic brake, not the extended-range dynamic brake that's used on some of the prototype locomotives. I was pleasantly surprised to note that the model's truck sideframes are molded in appropriate colors for their prototypes. Atlas also used two different styles of sideframes, matched to the proper prototype. Many GP40-2s rode on early GP ("Blomberg B") style trucks, as seen on the Conrail and GTW models. Other GP40-2s used the newer modified GP truck ("Blomberg M" as on the UP model). Made in China, the Atlas model is a bit of a hybrid, as it has the short (81"-long) nose used on prototype GP40-2s through 1976 (later engines had 88"-long noses). However, the model has the large front anticlimber and corrugated radiator grills found on the later Dash 2s. The paint on our samples was evenly applied and all were neatly lettered. Again, like the most recent Atlas releases, the GP40-2s come in two different road numbers with a third stock number that's painted and lettered with no numbers... A very nice touch is the factory applied numbers on the number boards. Under the hood the model offers the same motor and mechanism as the GP40. Several locomotives are offered with Digitrax decoders in place of the stock lighting circuit board... I tested both the standard and decoder-equipped models. Both performed flawlessly, and I was quite impressed by the incredible slow speeds the locomotive achieved. At higher speeds the locomotive was a little noisy, but in running other recent Atlas diesels I've found they get quieter over time... The model has a five-pole, skew-wound motor with a pair of turned-brass flywheels. With its 1.2 ounces of drawbar pull it should haul about 29 cars... All four axles are powered, and all wheels pick up electricity. The wheelsets were in gauge, but the flanges are deeper than NMRA RPs... Like its prototype, the Atlas GP40-2 offers advanced electronics and superior performance and opens up the joys of command control to N scalers without the need to modify the locomotive. Atlas has hit a home run with this model. B&M, CSX, Conrail, SP, UP, Alaska RR, FEC, GTW, Reading, WP. Price: $84.95 & $124.95")
GP38 reviewed: 09/01 Model Railroader- "This superb GP38 is another in the parade of well engineered, good running N scale models from Atlas that are crisply and accurately detailed. It's a departure, though, in that with it Atlas has introduced a lower rpm motor that yields slower running speeds. Slow speed crusaders will shout hurrah; those who advocate speed compatibility with Atlas' earlier releases may be upset... Atlas' new N scale version of this everyman's engine is made in China. The model checked out nicely against prototype drawings... It comes in several variations, including low or high short hood and with or without dynamic brakes, depending on what's appropriate for the railroad. Each engine comes in two road numbers plus a numberless version... Notable features include the numbers printed on the number boards, handrails that are the correct colors, and plows. The painting and lettering are excellent... You can buy the engine with a Lenz decoder already installed or a PC board that can be easily swapped out for a decoder board... The engine uses the same frame and mechanism as Atlas' previous GP40-2... This is the typical N scale mechanism design we've been seeing lately from Atlas, Kato and Life-Like. The motor, drive train, and trucks are sandwiched between electrically isolated metal frame halves. The five-pole skewed-armature motor has flywheels at each end and drives worm gears that power spur gears in the truck housings. The chemically darkened wheels matched the NMRA standards gauge and they all pick up current via metal bearing plates that support the needlepoint axles. Atlas calls this a "frictionless drive" and introduced it with the GP35 in 1992. The body-mounted Accumate magnetic knuckle couplers are compatible with Micro-Trains and other knuckle couplers and checked out at the correct height... The one big change lies in the motor. It runs slower at all voltage settings than those used in previous Atlas engines from China... With its .64-ounce drawbar pull the model should handle 15 cars on straight, level track. Add up the score and Atlas wins again with a precisely made replica of a popular prototype. Nor has the company been afraid to take a step toward more realistic performance. Undec, Alaska RR, AT&SF, B&O, BNSF, CSX, GM&O, NEC, Southern. $99.95"