Wiring Questions and Problem Solving

Let's take this as a math question.

If it's a post-war (traditional) ZW, it is rated at 275 Watts input. Let's call the output roughly 240 Watts, as an example. If the voltage to the track was set at 12 volts, and a dead short occurred,  that means that 20 Amps of current was running through one wire, out to the train, and back to the transformer.  Power (watts) = Volts x Amps.

The ampacity of 16 gauge is 22 amps in free air.

What happened was your wires became overloaded and got hot when the derailment occurred.

Many people say that they recommend putting fuses in line with the track circuits, and using larger wire, such as #14.

I would get the track off the carpet. Put a cotton sheet down or woden strips. Hope this helps

 This is a post war ZW, right? How small exactly is the layout? How many & how long are the wires? Powered turnouts, car lights, or other draws on track power?.

  I think you should check the operation of the transformer circuit breaker. If it is working right, I think it should have tripped way before "smoking" the wire insulation off of 14g.  (not as sure on 16g, or already "really hot" wires).If I wire a dead short, my KW will trip in 2 seconds. If its breaker is fine, adding an inline fuse, or modern automotive thermal breaker, of an amp rating well under the range of the wire size used. Yet big enough to hold your largest operating draw, i.e., the most power you will ever need to use at one moment. I believe as many others do, that modern vehicle breakers act faster than the old ZW original. Fuses offer an easy change, for getting a closer match to the ideal trip/burn specs.  

I think the lesson here is to cut power to the track immediately after a derailment, and not wait for a circuit breaker/fuse to protect the wiring or your trains.

Larry

Sounds like your ZW internal breaker is not functioning. Not too surprising. 

You need fuses or breakers in your wiring. 

I would use 10 amp if it's 16 AWG, or 15 amp if it's 14 AWG.

They should be right at the transformer.

Rod