Originally Posted by ennisdavis
Who made it and year
It's a Marx postwar loco as determined by the single unit for the sliding shoes (see pic, below).
Oddly, my 1666 is a 0-4-2 with no provision for a front truck. Your 1666 shell has a pylon underneath in the rear for a trailing truck. You may have a Marx 666 motor installed given the hole in the sheet metal for a front truck.
Both motor versions are great runners. They keep chugging along, effortlessly, with a bunch of cars in tow. Just make sure it's had maintenance - motor cleaning, oiled axles, greased gears and commutator face / brush cleaning (see step-by-step, below).
Marx Prewar PostWar.png
You'll need some CRC cleaner (HD), GooGone or TV Tuner cleaner. 90% Isopropyl alcohol also works well. That loco will come back to life with some maintenance:
(1) Remove the motor from the shell (two screws on the side and it slides out).
(2) Remove the two screws that hold the brush plate on the motor. Clean the armature face (three sections) with CRC and Q-tips, a kitchen scrub pad (pencil eraser for stubborn spots). Clean between the three sections with a toothpick. Clean the plate's brush silos with CRC on a Q-tip. Replace the brush plate sans brushes. Then lift the tiny springs to the side of the silos, insert the brushes and replace the springs. That should get the motor running. If not, start performing the next step while turning by hand until the motor will run on its own
(3) With the motor running over newspaper, hit it with lots of CRC - inside and out, a few times or more to clean out all the old, dried up lubricants: "flush it out"
(4) There's one spot where you can use the CRC straw pinpoint nozzle to get some in the E-unit (if equipped). Repeat as necessary turning the motor over and over while do it. Note the E-unit won't cycle unless the motor is upright.
(5) Lube the axles, push-rod points and the armature's spindle. Lightly saturate the felt surrounding the spindle on the brush plate side. Use a lightweight oil (sewing machine, 3-in-1, etc.) Grease the gears. Sans grease, use a heavy motor oil (or a lightweight in a pinch).
(6) Clean the wheels for better electrical contact and grip (pulling power).
(7) Run the engine on a track. It will run better after several minutes.
(8) Have fun.