Smoke pellets are available, made by a third party. They work just like the originals, including the smell.
But: you didn't say which 2020 Turbine you have. The first year they were made a special bulb was used to melt the pellet and make smoke. Those smoke bulb pellets were a different formula. They were corrosive, and probably toxic. So those pellets are not available. And if you found old ones, they would be decomposed by now. Some folks use liquid smoke with this model.
When Lionel developed the heater type smoke unit, they offered conversion kits to switch Smoke Bulb engines to use them. (Maybe you have a converted one).
If you have a converted smoke bulb engine (1946) or a heater type smoke engine, the new pellets work great.
Plus, some folks use liquid smoke in pellet heater type smoke units. Not something I'd do or recommend. One reason being that I don't like liquid smoke.