Work in progress - level crossing wigwags project (faulty relays)

Here I attempt to wire my wigwags. However, as soon as I wire in two lights to the same relay channel, a fault quickly develops.
For some unknown reason, the solid-state relays used here don’t seem to like the amount of current being drawn by two 24V 36 watt (1.5 Amp), despite supposedly being able to handle a 5 Amp load. As a result, the relay channel used started to overheat and subsequently died altogether.