Wow. Lots of great ideas. I may have to rethink this.
Kooljock, good point about just looking down at the control board. But I like having a lantern bulb on all of my switches so that I can instantly see that they are all powered up when I turn the transformer on. I think a white light would be too bright, so that is why I am thinking yellow.
I may try to notch the lantern first, as Rob suggested, which is something that (stupid me) never occurred to me.
As a sidenote, I taped a little white pointer on top of the lantern, which points to which track is open, and found it amazingly helpful in working that center switch. I can see at just a glance which way the train is going to go. (It only takes one brain step, i.e., which way is the pointer pointing, instead of two steps, i.e., what color is the lantern and which direction does that mean! Very helpful as your brain gets old. :-)