Keep in mind that light near brush entities (in the level editor) will light those entities in the world when spawned.
For example, if you have a func_train in a separate room and put light entities around it, and then spawn the func_train on a path upon loading the map, it will have those lights baked onto the texture.
This happens because when you compile the map with RAD, it only looks at things "statically" and bakes the light information onto textures.
This is true for elevators too. If you don't put a light inside the elevator, it will not be baked and therefore appear black (in case there's no light entities around). However, any players moving around a map will pick up the light onto their model (and viewmodel), so ensure to put lights across the path of an elevator to ensure that they are lit.
