The globes are hollowed with a center hole for inserting an LED. Greg Shinnie did an excellent job of lighting the HO 16" version which he then described on Railroad Line Forums
HO Schoolhouse Globes
Safe Harbor Statement: I have placed these parts in BETA. That means that they have not been printed yet. Until the time that I have had them printed and have held them in my hand and examined the print I can not guarantee that they will perform as shown. This means that during the BETA phase by ordering these parts you are essentially a BETA tester and are working with me to improve the process.