You must be logged in and verified to contact the designer.
The center has a 1/16" hole for inserting an LED. Greg Shinnie did an excellent job of lighting one which he then described on Railroad Line Forums. I modified the version I in the link to include the hole so drilling isn't needed. Note: These are listed as 16" HO scale Light Globes but they could easily be used in other scales .. in O scale it would be 8.8" and S scale 11.7".