zw transformer

I hve a zw transformer and i was woundering what i can put on the hot wire to protect trains that have chips and boards from burning out from surges.

Put a transient voltage suppressor (TVS) between each output terminal (A through D) and the common terminals (U). Do a search of the forum for advice about sources and part numbers.

It’s also a good idea to put a circuit breaker or fuse in series with each output terminal. The best circuit breakers for this application are auto-resetting thermal automotive fuses, which you can find at auto parts stores. Use a circuit breaker appropriate for the wire size that you are using, but no more than 15 amperes.