I have some lamps that I will shortly be adding to the platform at Hexworthy, and I had thought it would be nice to add lighting to the station building too - after all, there's no point in the platform lamps being the only source of light. I'd added the DC voltage regulator connected to the 16V AC supply via a switch on the control panel when I wired up the playground, and I had some assorted LEDs and resistors to hand.
The result works quite nicely. Being a plastic phonebox it does glow through the red, although it isn't so obvious to the eye as it looks in this photo. I may go for a bigger resistor to dim it a little. I like the way this is largely hidden by the water tower from some angles, but comes into view as a splash of red in daylight or now as a glowing beacon in the dark - rather like real old phoneboxes did.