after reading up on the lore, we can assume the Manhattan project had a sister tagged along with it, but it took too much funding, secrecy and rivets from the Manhattan project, so it was shut down, after the war, servicemen coming back from the horrors of war would need a major morale booster, Fer Rouge was one of a kind, built in the desperation of war, now discarded in an alleyway somewhere in an American diner, she roared back to life via unknown forces, thrust into a world much different than the one she was made for.