Introduced: 1999 (CW44AC, AC4400, C44AC, C6044AC, C60AC) and 2003 (AC44CTE)
Apart from the AC44CTE, these OMI/Ajin GE models all came out at the same time. And as such, I'm going to go ahead and assume that they all share the same basic internals. So, to save myself a bit of time (and money), I'm going to review them all here based on the two that I've actually purchased and tested.
As pictured above, shell detailing and paint are typically first-rate. The mechanism itself is fairly typical of 1990's Ajin design (IE, reliable, yet somewhat primitive) -
The chassis is all metal, although relatively flimsy (with most of the actual weight being provided by the fuel tank and the shell). The motor is an open-sided / skew-wound 3-poler with dual flywheels. Eight of the twelve wheels provide pickup (with the center wheels on each truck being electrically neutral). There are no traction tires. Pickup is provided by wheel-back wipers. Current is transferred from the trucks to contacts underneath the chassis via more wipers. Current is then conducted to a lengthy PC board atop the chassis by way of long, sprung contacts. Contacts on the chassis PC board transfer current to the motor as well as an LED-equipped PC board mounted inside the shell (which provides directional lighting). All wheels are geared and all gearing is plastic. The wheels are low-profile, so no problems on Code-55 rails. The couplers are chassis-mounted Micro-Trains.
As delivered, overall performance is very respectable. Throttle response is smooth at all levels. Pickup is great (no problems through turnouts). Pulling power is strong. And although they don't run quite as quiet as a modern Atlas or Kato diesel, they certainly can't be categorized as loud or noisy. Yes, the top-end speed is excessive. But then again, if that bothers you, don't turn the throttle up that high.
On the down side, these models are completely useless on 11"-radius curves or sharper (where they will either slow down and make all sorts of unpleasant noises, or worse still, simply derail). Also, I'm not really sold on those primitive truck-to-chassis wipers -
Flimsy/bendy wipers like these are simply not reliable, as they will inevitably get squashed down and lose contact with the chassis. Oh sure, they can be rebent as needed, but it's an annoying process (and one that's going to be a life-long commitment).
Trivia - Ajin starting redesigning some of their Overland diesels to use split-frame / all-metal mechanisms starting around 2002. However, I can definitely say that the 2003 GE AC44CTE did not receive this upgrade.
Removing the shell is a somewhat complicated procedure (no surprise there). First, remove the Micro-Trains couplers. Then, unscrew the two now-revealed screws (one at each end) that hold the shell to the chassis. Lastly, remove the four screws that hold the fuel tank in place.
Grade: A (with the caveats re the chassis wipers and narrow radius curves)