CJack,

Many thanks. I wish I better understood how you wired this. I ordered from Mouser Electronics. Tjhe part number is below. I cannot see anything on the switch terminals labels like "supply/earth/load" As a result, I cannot tell which is which. When you say, "connect all the Earth terminals together and use one 1N4003 diode to supply common, the U or outside rail terminal." Do you mean all the commons from all of the various track circuits all together? I just don't understand how I would do that and where the diode would go and so on . . . .