Introduced: 1972 (Yugoslavian version) and 1984 (Austrian version)
Con-Cor's Century 636 was originally manufactured entirely by Mehano (Yugoslavia). It made use of the same chassis / mechanism originally designed for Mehano's RSD-15 model (as imported by MRC starting in 1969) along with new trucks and a new shell (and with said shell being way undersized in order to accommodate the existing RSD-15 chassis). I'm not exactly sure how long Con-Cor soldiered on with this first "all Mehano" edition, but I'm guessing it wasn't for more than a handful of years (or even beyond the initial production run). Circa 1984, Con-Cor introduced a revised C-636 with an all-new chassis/mechanism (manufactured mainly in Austria). Unfortunately, both versions share the same ugly Mehano shell (with do-it-yourself, glue-on, brittle handrails). Both versions also sport open pilots, truck-mounted Rapido couplers, and super-sized wheel flanges (IE, forget about Code-55). And yeah, both versions are quite lame.
Although Mehano upgraded their RSD-15 mechanism many times over its long lifespan, it was only the very first (circa 1969) version that ever made it into any of these Con-Cor models. Eight of the twelve wheels provide pickup (the other four having traction tires). Both trucks are powered (although only four wheels per truck are actually geared). Lighting is (surprisingly) bi-directional. Current is ferried around via wires. All gearing is plastic. The motor is a 5-poler, albeit a pretty cheap looking one. The chassis is entirely plastic, so heft is provided by a couple of ala-carte metal weights.
The original Mehano RSD-15 mechanism used to have the reputation (way back when) of being a pretty solid performer (two-truck pickup / propulsion apparantly being something of a novelty back in 1969). However, I can't really say that they've aged all that well. All the ones that I've tested tend to make a lot of noise, and with overall performance being very uneven. Pickup is generally pretty bad, with the end-result being a lot of stalls (at anything below full throttle). Granted, these are all 30+ years old at this point and might benefit from some tuning. But honestly, what's the point?
Useless trivia- Con-Cor introduced an EMD SD45 model at this same time, mounted atop the same plastic Mehano mechanism.
The second version is quite an improvement over the original, at least in the performance department. Still, it's nothing to get excited about -
The metal chassis, redesigned mechanism, and 3-pole / skew-wound motor do make for a smoother and quieter running model than the first version. Some of these have traction tires and some don't (I believe the first production run didn't have them, whereas all subsequent runs did). The ones with traction tires tend to be a bit wobbly. The ones without TT's do seem to have fewer pickup issues. But TT's or not, they're all still a bit herky-jerky overall. And of course, they still have the same awful shell and the same "wires running all over the place" issues of the original (and yeah, good luck getting one of those truck wires resoldered should it decide to become "unstuck"). The fact that they decided to go with a single (non-directional) light doesn't much help either. So, a nicer shade of mediocrity I suppose. But, ultimately not much more than that.
This same Austrian-made chassis/mechanism was used in all of Con-Cor's EMD diesels of the 1980s (SD45, SD40-2 and SD50), albeit with different trucks.
The Mehano versions are stamped "Made in Yugoslavia" on the bottom of the fuel tank and have all-white gears, whereas the Austrian versions are stamped "Con-Cor Austria" and have a mixture of red and white plastic gears.
This model was ultimately dropped in the late 1980s (along with the rest of the Con-Cor/Austria import roster) - being made obsolete virtually overnight by the new line of Atlas/Kato diesels.
Grade: D (for the Mehano) and C (for the Austrian version)