Much as I do enjoy winding up my friends in our American colonies vis a vis their country's lack of any military ability (as opposed to strength - their is a difference ) and the romantic (read blatantly dishonest) accounts of US actions in the last war as promoted by the likes of Disney, Spielberg et al I'm afraid I have to take you to task.
For instance may I suggest that you google for "Greer incident" that should bring up plenty of hits, hit the links and you also read of US destroyers targeting German submarines as early as Spring 1941 and even of US naval losses prior to Dec '41 as a consequence of their undeclared war against Germany.
Another interesting factoid often missed relates to the Bismarck sortie in May '41, as the Bismarck and the Prinz Eugen were making their run through the GIUK gap the US Battleships New York and Texas together with a flotilla of escorting destroyers crossed from the Western to the war zone in the Eastern Atlantic and also headed or the GIUK gap. By strange co-incidence the New York and Texas despite their age and antiquated engines where the only two US battleships in their Atlantic fleet equipped with radar.
It's easy to be disparaging in the light of post war events such as Suez and propaganda films such as "Saving Private Ryan" and "U571" however *at the time* many things were significantly different to your apparent belief.
Now then, what's this all got to do model railways? :-)