Introduced: 1973 (discontinued circa 1982)
Although not a particularly impressive runner, this is reputedly one of their more accurate F9 models from "back in the day" (at least if you go by the vent configuration). It has the required five side vents, four between the portholes and one ahead of the forward porthole.
The mechanism is pretty typical of 1970s-era Roco design. The all-metal chassis holds the open-sided 3-pole motor and the worm gears. The dual-ended driveshafts are connected to the worms via various plastic connections. All of the rest of the gearing is plastic. All wheels are geared and provide pickup (no traction tires). Current is ferried from the trucks to the motor via miles and miles of twisty wiring (and good luck getting any of those truck connections re-soldered if they should happen to come de-soldered). A non-directional headlight is mounted to the front of the chassis. Rapido-style couplers are mounted to each of the trucks.
Performance is also pretty typical of 1970s-era Roco design. First and foremost, these things are extremely noisy (kind of odd, given the fact that all of the gearing is plastic). I don't know if the fault lies in the design or the manufacture, but something just ain't meshing together quite right. Pickup can be decent (if yours has aged well), but more often than not performance tends to be a bit jittery these days (either due to contacts coming desoldered, wheel wipers not wiping properly, or some other nameless malady). I'm not real impressed with the motor either. Mine requires a huge amount of throttle before it starts moving (and when it does decide to get going, it goes). Not surprisingly, the top-end speed is pretty much off the charts. Pulling power is decent. The wheels flanges are somewhat oversized, so it's unlikely these could be operated on Code-55 track.
So, all things considered, not a terrible locomotive. But definitely too many deficiencies for it to find a place in a modern operational fleet.
AFAIK, this model received no modifications or upgrades during its production run. It was ultimately discontinued in the early 1980s when Atlas dropped their entire line of Roco-made locomotives (a direct result of Atlas's new partnership with Kato).
To remove the shell, simply spread the sides apart (freeing it from the tabs on the chassis). It should pull right off at that point.
Reviewed: 12/74 Railroad Modeller (hey, send me a copy and I'll summarize it).