If the transmitter works, people near the tracks are spared the noise of the horn. If the transmitter fails, the engineer sounds the horn as he would if the system did not exist. If the system is designed to fail "safe" (which would not seem overly difficult) what's the problem?
It's not. No system involving electronics is EVER "fail safe". About 4 months ago, they put up signs under the yellow RR crossing warning signs: "NO TRAIN HORN". They're trying to cover their posteriors for when the gate fails, but I don't think drivers are going to understand that that means "LISTEN" doesn't apply here.
It fails on a conservative estimate about once a month. The window between the failure of the gates and when the trainmaster notifies the engineers is the window where a fatal accident is going to happen, sooner or later.
Duplication of systems (gates, crossing bells and lights, train horn, train bell) is the best way to cover that window.
The train was here LONG before this suburb existed. I had no problem with proximity to the southbound horn from 1994 to last year. I used to investigate crossing accidents, and when you've taken photographs of some poor moke's remains crushed inside his car a few times, it gives you a different perspective.