Thank you @RickO . Those are the same types of LEDs amazon sells (except much cheaper). https://www.amazon.com/L1218WM...&sr=8-2&th=1
Lionel has created their LED for their lamps with the resistor, it appears, wired into the base (bottom) of the lamp post. I took one lamp apart and now I see they are using the 3mm LED version. I'll just have to modify the 3mm version that Amazon sells and dismantle/disconnect the resistor being connected at the bulb and rewire to move to the bottom of the base in order to thread the wires through the lamp post.
I was asking because I liked the light better from the LED version than the 18 volt grain of wheat bulbs Lionel had put in the older lamp versions and just wanted to rewire them with the new LEDs.