5mm and 3mm LEDS. Left clear is the ble I used in the tower project. Te center clear is a yellow beam used in the 600 MKT switcher. The longer lead is the Positive end. The bulb actually has a flat side to denote the neg end.
I took a Xma light socket and enlarged it with a Tungsten Carbide bit to fit a 5mm LED inide. I used silver acrylic paint.The tubing is actually the plastic cover for 8 strand telephone wire.Use a stiff wire to shape the post. Make a base. Also viewed in "O scale Simple How to"