Here’s a short test showing how the train horn switch panel in my old daily beater worked...
I wanted my main trigger switch to be the horn button on the wheel rather than a remote button in the case of a panic situation, but still wanted the ability to go back to the stock horn if needed...
Each red toggle switch arms a relay for either the stock horn, Hornblasters HB4H horns or Nathan Airchime K3HA horns...