The original Gilbert scent is now called Cedar. It is made by SuperSmoke, JT Megasteam and Challenger. I used the last of my red Gilbert ampules 20 years ago. The modern replacement fluids are a little off from the Gilbert originals. Supersmoke is a higher viscosity than the other two. It works well in Gilbert smoke units but the modern Lionel smoke units work better with a thinner fluid so I have been using Challenger. JT MegaSteam is also great for the Lionel smoke units.
If you want to compare scents try a Gilbert engine against a recent production Lionel engine. The same fluid smells slightly different in a recent production U36c on high than in an original 322AC. Might be caused by a difference in the temperature of the new Lionel smoke resistor vs the old Gilbert wire wound wick.
There is no such thing as too much smoke.
