I used Lionel smoke units on all but one of mine. I did use a MTH unit I had for a narrow shelled UBoat. MTH units are longer and narrower than Lionel. Now if you can get the two brass posts to work, it is easier to install the Lionel units. If not, I use "L" bracket used for carpenter work. If you are going to run conventional, track voltage is all that is necesary to operate the unit. If command [18V], then the voltage needs to be reduced. I use bridge rectifiers to do this. Following is photos of the first unit I did. It was an MTH dummy and I added lights and smoke. Still works great to this day. I did install off/on switches for lights and smoke. Since this unit has been done, I have found a RC plane connector necessary to make the unit work. Then Lionel connectors [three pin] are impossible to find it seems. This connector is by JR, JRPA094, servo extension 6" Standard G. I use one end. Fits perfect. Making the connections, two outside wires go to track power. The one middle wire is common and goes to frame. Building bridge rectifiers to reduce voltage: soldering + and - soldering them together [BTW: usually three is all needed for Lionel, all five for MTH] testing unit unit installed using "L" bracket. All holes elongated with drill press to allow adjustment upand down/side to side. I do not use the big connectors any more as take up too much space. I just solder and use heat shrink to protect. The gasket on top of the unit is closed foam insulation and sealer by ACE. One side sticky. On most of these, I have removed the exhaust stack from the shell. Makes it easy to hit the hole with dropper of fluid. I have ordered funnels from Lionel and yet to receive them. Maybe one day. I just snap the exhaust stacks back in after loading. I open the smoke units when I get them. Cut the sock like wicking from the element. Worthless. Pull out all the packing and reinstall with pink insulation [yes, the house stuff]. Connect the wires to power source. Check the rotation of the fan. Should be clockwise. The bend in the vanes will fool you. They are pushing the air in and are bent "backwards" like any pump impeller. If rotating backwards, take a straight pin and insert into the plug from fan to the printed board connector. This will release the prongs and allow you to remove the pins. Switch the red and black wires and re-plug into the connector. Reinstall the top to the unit insuring the element touches the pink packing but the packing is not blocking the air hole from the fan chamber. Soak well with fluid. I find most folks run their units too dry. Hope this explains the process well enough to help you smoke your own units.