Just regular fuses for use with 25 to 50 volts A.C, 7 or 8 amps, up to 10 amps but no higher. Put a fuse in each letter, A to D, output of the ZW.
Radio Shack may have fuses, but make sure they are for under 60 volts.
The Lionel # 91 breakers may seem expensive at first, but what would it cost to replace something?
Lee F.