@Arthur P. Bloom posted:In the fine print it says they're compatible with A.C. or D.C. My friend Justin Case would stick a diode in series with the common lead.
I strongly suggest you mind Justin's advice. You only need 1 diode to protect all your signals. If you have a DIY electronic buddy they would have and gladly give you a suitable 5-cent diode...otherwise something like this would work from a US eBay seller:
Insert diode like this:
Your diagram shows 4 signals. You can use the remaining 8 (or 11) pairs of the 12-port MTH terminal block to distribute Accessory AC to any other accessories. That is, you show the Z-1000 brick ONLY powers the MTH terminal block (18V AC track power output unused). The Z-1000 brick can supply 80 Watts of power thru the Accessory AC output. 4 signals as you indicate will use at most 1 Watt of power! What are you going to do with the other 79 Watts?! 
