It is based on technology from over a century ago...it is just an electromagnet around a ferrous rod that pushes up on the gate. Voltage on- gate down, voltage off- gate up (via gravity). There are no switches, relays or fancy circuitry inside. Essentially, it is just a counterweighted arm and an electromagnet/solenoid that pushes up on a cam to hold it down. As such, it will buzz when on/down.
Note that it can overheat or fail under prolonged use. Such overheating is, of course, related to the length of time between activations, duration of the activation and the voltage applied to activate it. At typical 14V track voltage, I would limit its activation to no more than 2min every 5min (continuous)/ 25sec per minute (intermittent) to allow for the solenoid to cool off.
While there are time-out options to prevent overheating or failure (like real ones use to prevent continuous activation), the easiest method is to change from track activation to a momentary contact switch (push button) or add an on/off switch to the track activation circuit.
