One of my kw transformers needed a new breaker as the original one was engaging at 6 amps. I replaced it with the often recommended 10 amp 12 volt automotive auto reset breaker. To test I have a Ohmite 1 ohm 300 watt resister that hooked to the track power circuit on transformer post a and u on the kw transformer. With a direct short (a hooked to u), it engaged almost immediately . With the resistor across the post a and u producing about 14 amps (at 14 volts with 1 ohm resister) the new breaker would not engage even after a minute or so. Defective new breaker? Or normal at 40 percent overload?.i know Lionel allowed up to 45 seconds at 20 amps with the original breaker to open. I would think a modern breaker would pop at 11 or 12 amps quickly but I am not an electrical engineer. Any comments appreciated.