I believe "022" refers to the Lionel part no. for this particular switch assembly. It is made for O31 track (and not O27), hence the "O31" description. The replacement bulb number is probably Lionel's own assigned part number for an otherwise common (or not so common) standard light bulb, which probably explains why you can't find the bulb doing a google search using Lionel's part number.
022 switches manufactured prior to 1950 had screw-in style bulbs, lamp no. 752-9. 1950 and later 022 switches changed to a bayonet-base bulb, lamp no. 2026-58. I believe these are also Lionel part nos., so you may not be able to find them either with a google search. This is based on info. obtained from my Greenberg's Repair and Operating Manual for Lionel Trains 1945-1969.
BUT........... assuming your switch is a 1950 or later, there's a fair chance that an old school, standard little 12V incandescent automotive bulb might fit directly in place of your switch bulb, if it indeed is a bayonet base. It's the type with 2 little pins on either side of the base, and you push down and turn the bulb approx. 1/4 turn to remove or install. If you run your switches at 14V, not to worry, the 12V bulbs will still be just fine. Keep in mind that although they're rated at 12 volts, a vehicle's charging system is usually putting out right around 14~14.2 volts, and the 12V bulbs still last a long time. And incandescent bulbs work equally well on either AC or DC current, so that's not a problem either.
You should be able to pull the little rotating lantern straight off the top of the switch motor cover, exposing the light bulb. Remove the light bulb, and if it looks like an automotive-type of bulb, simply go to a well-stocked auto parts dealer and see if they can fix you up with a new bulb. Might have to buy a package of 2 or 4 bulbs or however they're packaged, but you can keep the extras for spares.
Hope this helps. Good luck in finding a replacement.
