Bwuhahaha! You probably need a new spring if it's buzzing. IIRC the E-Unit (not coil as I mistakenly referred to it previously) uses a pulse of superimposed DC current to activate it. The normal AC power can cause this chattering/buzzing unless the unit is in good shape.

The neat thing about Lionels is that you could leave an engine in "neutral" but with power still applied so that the lights and smoke would stay on. Also, because of the 3 track system you could isolate segments and use the tracks themselves to activate various accessories like crossing gates, the man in the tower or shanty shack etc.

Anthony