...You are saving this does not matter and the transformer will reduce the voltage regardless and proportional to the input AC voltage? So, it will operate with an input AC input voltage of 14 volts?
Correct. For the matter at hand, it's the ratio of input to output voltage. So if a transformer hooked to 120VAC input delivers 12VAC output or a 10:1 ratio, it will output 1.4VAC when hooked to your 14VAC accessory voltage. So you go hunting around Radio Shack or wherever and notice common transformers are 24VAC/25.2VAC or maybe 48VAC. You do the math and decide for yourself if you can make the numbers work for you. If your train transformer accessory output voltage has adjustability from 14 to 16VAC (or whatever) then you get a little wiggle room. Or if the output is a bit high after the transformer you can use pairs of nickel diodes to drop the AC voltage in ~0.6V increments.
