Since I found "hero" sandwich I think I'm on a roll.
So, from the Newport(RI) Daily News, March 10, 1950:
<A classified ad>
EXCLUSIVE! Torpedo Sandwich, a meal in itself. "It's the Talk of
the Town." Cafe 200. Pizzaphone 232.
SC
Actually, I'm not sure if I'm antedating anything. No one seems to care to
list this sandwich.