Instructions
Look at the train's smoke unit to get an idea of its depth and construction. Electric train smoke units create smoke when a smoke fluid is added to the unit and heated with the internal nichrome heating wire. Once the fluid is added to the heating unit, the heating wire will have to warm significantly before the smoke is produced.
Carefully pour some of the smoke liquid into the smoke unit through the train's smoke stack. It is important the enough liquid is added to cover the heating wire. If too much liquid is added, though, it will take a long time for the heating wire to adequately warm all of the liquid and produce quality smoke.
Turn on the electric train on and allow it to run long enough for the heating wire to warm the smoke liquid. As the wire begins to work, the smoke stack will start to emit smoke.
Add more liquid as necessary to keep the smoke stack active. Before turning off the train, allow the excess liquid in the smoke unit to burn off so it does not dry in the unit and damage the heating wire.