Introduced: 1984
These models (DS-4-4-10, DS-4-4-6, VO-1000, S-12) all came out at the same time, and as such I'm going to go ahead and assume that they all sport the same basic chassis/mechanism. So, to save myself a bit of time (and money), I'm going to review them all here based on the single DS-4-4-6 I actually purchased.
These are great looking and fine running models. The internals are very typical of 1980s Samhongsa design -
The motor is a small open-sided 3-poler. All wheels are geared and provide pickup (via wheel wipers). The sealed truck gear towers pivot right along with the trucks through curves. The dual driveshafts are plastic. There is no lighting and there are no traction tires (no couplers or window glazing either). Current makes it to the motor courtesy of miles and miles of wire (two wires per truck).
Performance is quite excellent, particularly given their small size. Throttle response is smooth at all levels. Slow speed creep is impressive, and the top-end speed is quite reasonable. Pickup is great, as I can creep mine through plastic-frog turnouts with nary a stutter. These do make a bit more noise than more modern models (especially at very slow speeds, where the motor tends to growl and hum). But I've certainly heard worse. All that brass provides plenty of heft, so pulling power should be decent. These have no problems navigating narrow-radius curves.
A lot of old Samhongsa models have problems with their plastic gears deteriorating over time. But apparantly not so with these. Either the gears aren't plastic, or Samhongsa went with a less dodgy supplier when they ordered up the parts for these models.
Overall, these are really great models and definitely operations-worthy. However, I can't quite give them an overall "A" rating. The technology (vis'a'vis the wheel wipers and the wiring) is definitely not "state of the art", and they make just a little bit too much noise to be A-worthy.
FWIW, it's my impression that these models are fairly rare - they hardly ever show up on eBay, that's for sure.
Here's the non-PRR VO-1000:
To remove the shell, simply unscrew the three small screws holding the shell two the chassis (two on one end, one on the other).
Grade: B