FWIW, I have a Ross 11 1/2 degree crossover with a DZ1008 relay to swap ground/power to the rails in the center diamond. I have also experienced shorts multiple times. The route in which the relay is normally closed always works. The route where the relay must operate to shift power (normally open) is the one that fails/shorts. The short means the relay has not engaged to shift the power. There are a variety of causes of this. One is that all the grounds involved must be connected to each other: train power, relay power, and switch machine power. Best solution for me was to use train rather than accessory power to the relay and switch machine connected to the relay to latch it (no switches with machines in my case). The relay itself is almost never the problem. Connecting its green to 12 volts positive, you will almost certainly hear it engage.
Try some of these and let us know what you find.
