Lionel ZW 275 running Legacy engines

A tmcc direct Lockon would be one option.

~Bill

I have the same set and purchased the PSX-1AC (American Hobby Distributors) and use it on the output of my ZW. It provides instant protection for Legacy Engines. I purchased it from Charles Ro. I also use Legacy Control.

The PSX-AC and TMCC Direct Lock-on both provide excellent protection, but may be a bit overkill for a small Christmas layout (I use the PSX).  A somewhat cheaper alternative is to use a fast acting fuse with TVSs (forum choice is the 1.5KE36Ca).  I use a TVS at the transformer and each track connection; for your application I think only one at the transformer is needed.  However, extra TVSs won't hurt.

Along with a TVS I would use a fast acting 7 or 8 amp circuit breaker on each output terminal with the letter A, B, C or D. The post war ZW has enough power butt has the circuit breaker on the common side and can almost weld something before it trips.

Lee Fritz

I would suggest some in-line fuse holders with AGC4 or AGC5 fast-acting fuses. 7 or 8 amps is too much. The fuse holders have 12 gauge wire, so, they can connect right off the terminals on the ZW. get a few boxes, because these will go with a minor derailment or oops with a tool. They'll keep the train electrics safe.

You may draw 4 or 5 amps with a dual-motored engine and lighted cars. If you run multiple engines, then a higher amp fuse would be appropriate.

The TVS is good suggestion also. I would put them closer to the track connection or across it.

Simple answer is, you need something for sure.