Escape From The Room: Enigma Express: A Curious Contraption

It's the 1950's and Post War Britain is beginning to look to technology as a way to move the Country forward. Designs for a breakthrough invention have been obtained by British Intelligence. It's your team's mission to collect a briefcase left for you aboard the Enigma Express. You will find the designs for this curious contraption inside an otherwise inconspicuous briefcase but you will not be given the code, only what appears to be an incomplete crossword puzzle. You must use your skills to open the briefcase, and retrieve the plans from inside.