My used-1-month-each-year 682 used to produce thick, wafting, billowing, perfect "O" plumes of smoke. Now? Not so much. For years I used a scented MTH liquid that smelled terrible, and last year I bought a little white bottle of Lionel liquid smoke. When I set the ZW transformer in neutral at the max 20 volts, thick smoke smoke does appear. However when I run it forward at the same @14 volts as always, the smoke dissipates; only for 2-3 laps around the oval will it lightly tap-tap-tap, and then it virtually disappears. I tried a pellet, and the results were the same. I eve pulled out the aforementioned scented MTH liquid, and it still showed relatively thick smoke in neutral that becomes imperceptible when the consist starts moving forward. Now the place stinks.