While you are investigating Nikola Tesla's suitcase for clues, a pair of scissors is thrown at you. You will need to grab them, because you will use them later on.
Eventually, you will chase Erik Weisz (also known as Harry Houdini) on top of The John Bull, and he will fall into the Freight Car. You must use the scissors to the rope and drop the cloth of the water tank, in which he lands in.