These models share the exact same chassis / mechanism. The shells are quite similar as well, with only minor differences in detailing (vis'a'vis the different prototypes). Optional Body/Cab details include -
- Low nose headlight (where appropriate by road name)
- Horizontal or Vertical-mounted cab headlights (used where appropriate)
- Pilot with or without footboards (used where appropriate)
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).
Performance on these models is perfect in every way - smooth, quiet, flawless pickup and throttle response, exceptional pulling power, etc. My one minor gripe is the fact that the front and rear handrails do not come preinstalled. And getting said handrails installed is quite a bit more challenging than I think it should be. The things are skinny, bendy, and mighty hard to wrangle. And once installed, they don't seem particularly interested in staying installed...
A reported issue with at least one production run of these models relates to the tiny "press-fit" plastic U-joints (540104 and 490003) that make up part of the mechanism's drivetrain. The problem is that said plastic parts have a tendancy to degrade/crack over time. If the Male Universal fails, it will no longer be fixed firmly inside the flywheel (and thus not spin when the flywheel spins). If the Universal Ball Joint fails, it will no longer be fixed fixed firmly to the end of the wormshaft (and thus not spin the worm). The solution is to order replacement parts from Atlas. Or, failing that, simply use some super glue to fix them more firmly in place.
Prototype information -
"Primarily used for heavy-haul road freight service throughout the US, the C-628 generated a total of 2,750 hp, and was part of the American Locomotive Company’s (ALCO) Century Locomotive Line. A total of 185 units were built by ALCO for railroads in the US, Mexico and Australia between 1963 and 1968. During 1965 Alco started producing the 3,000 hp. Century 630 Locomotive. It was produced concurrently with the 2,800 hp. C-628, but it incorporated an advanced GE a.c. traction alternator which provided the extra 200 hp. The most distinctive spotting feature of the C-630 is the large aftercooler radiator housing which extends above the roofline (the aftercooler radiators enhanced the performance of the locomotive while operating under a heavy load). The C-630 also featured a modified cab which offered more interior space for the crew. Through the end of production in the late 1960s, a total of 133 units were produced for railroads in the US and Canada."
One note on the C-630 - the "Tri-Mount" trucks on the Atlas model are only prototypical for a few American roads (Reading, for example). Most American C-630s were actually equipped with "Hi-Ad" trucks (or so I've been told).
Trivia - an outfit called Briggs Models makes an M-630 resin shell kit designed to fit this Atlas mechanism -
Shell removal is very simple - just take hold of the shell with one hand and the fuel tank with the other. Then just wiggle the shell up and off.
Grade: A (for both)
C-628 reviewed: 08/04 Model Railroader ("An Alco Century 628 has been added to the Atlas stable of great-looking N scale road diesels. It's a big and powerful C-C locomotive that offers railroad-specific detailing... The Atlas C-628 closely matches prototype drawings... The body parts on our sample are highly detailed styrene, while the mechanical parts, truck sideframes, and railings are flexible acetal plastic. The window glazing and headlight lenses are clear styrene... The C-628 mechanism uses the popular N scale split-chassis design... Our sample started and ran smoothly at 4.6 scale mph on 2 volts, reaching at scale 50 mph at about half throttle... The model's drawbar pull is equivalent to about 24 cars... Body-mounted Accumate couplers are factory-installed at the proper height. All of the wheelsets on our sample matched gauge standards except for the flange depth, which is .005" oversize. The paint was evenly applied with clearly printed lettering... This smooth-running heavy-duty Alco road locomotive is an excellent model. LN, ACL, PRR, SP, DH, LV, Undec. $104.95 ($139.95 with decoder)")