I think it is always a good idea to read the Lionel factory service manual page(s). Adriatic has already provided a link.
When I adjust a 362 barrel loader (Postwar), I first make certain that the screws which attach the ramp to the base are tight, and that the diode is good.
I set the power supply voltage to around 12 volts.
Then I adjust the gap by moving the coil until it is just far enough away to avoid buzzing. (It will buzz if you turn up the voltage too high).
Also:
As noted in the service manual: Do not fasten down tightly.
I also wonder whether you are using a traditional transformer with a sine wave output.
Who knows how this accessory would work with a different type of power supply.
