The Lionel heating element shown in the first photo is designed to operate in contact with a rectangular patch of fiberglass material, which serves as a wick. The fiberglass wick in the Lionel smoke unit is stuffed into the bottom of a cube-shaped casting where the smoke fluid collects. The postwar Gilbert AF locomotive smoke units I have worked on have two separate chambers, a lower chamber that serves as a reservoir for the fluid and an upper chamber where the heating element is. The two chambers are separated by a wall in the casting that has two holes to allow for passage of an angel hair fiberglass wick. The heating element (Nichrome wire), is wound around the angel hair wick, with enough windings to produce between 30 and 50 ohms resistance. I tend to keep the resistance in my rebuilds on the low end of this range to produce more smoke output at lower speeds and voltage. I understand the late production smoke units had a different casting design which eliminated the wall separating the reservoir chamber from the heating element chamber, although I don't own an engine with this design and have never taken one apart.
Trying to use the Lionel ceramic core heating element would create two difficulties in the Gilbert smoke unit, in my opinion. First, I *think* the Lionel 16 ohm heating element may be designed to operate at a lower voltage. My Lionel Flyer Big Boy has this type of heating element and is connected to a circuit board, which implies that the smoke unit is probably not seeing full track voltage. I admit I haven't checked the voltage across the smoke unit terminals to see what voltage it operates at, but a 16 ohm element would consume considerably more power (and thus generate considerably more heat) than a 35 ohm element at 18 volts. I'm skeptical that a 16 ohm element would last very long if operated on straight track voltage up to 16 or 18 volts. The second problem I could see with trying to adapt the Lionel 16 ohm ceramic element to a postwar Gilbert smoke unit casting is that the Lionel element is designed to be embedded into a wick material containing smoke fluid. In the Gilbert smoke unit design, the majority of the wick material is separated from the heating element chamber. I don't know how you would create the necessary contact between heating element and wick given the wall separating the two (unless you removed the cast-in wall using a Dremel or a milling machine). It might work without modifying the casting if one used one of the late production Gilbert smoke unit castings that do not have the wall.
Scott Griggs
Louisville, KY