First a little background; my five yr old grandson likes to put Lincoln logs in the hopper cars (2) on our O-27 track.  The single motor locomotive will pull them but the two motor locomotive (which is a passenger train model) pulls them with LOTS more power.

Where/how can I find out if a new locomotive being sold is one motor or two, and how much power they can draw?

(I know with power tools the higher the amperage they're rated for generally the more powerful the tool). 

I suppose Lionel might use the same motor for all their trains, but the ads don't say whether the locomotive has one or two motors.

And how do I make sure my transformer is powerful enough if I don't know what the locomotive requires?

To confuse myself even more, I've always thought voltage is not a true measure of power (except indirectly), and that amperage is how power is rated.  But everything Lionel talks about is voltage.  I'm missing something.

Or maybe I'm just too anal about the math

regards,
Waddy