Go into the Proter clost then it should be hanging up underneath the bed.
to get to his room dress up as the porter
you have to dress up as the porter to get into Tesla's room. The french lady will tell you to
Dress up as a servent or employee of the train
After you dress up as the porter on Mystery Train Island, you go in to Telsa's room. You grab the prune juice on his dresser and give it to him. Then he goes to the bathroom and you need to find his luggage key to check his suitcase. It is behind his poster down left.
In the luggage cart, there is a door that is labeled "porter" go in it and you will see a bunch of supplies. There should be a coat and hat near the supplies hanging up. Get the coat and hat and put them on to look like the porter.
you dress up as the porter (you get the porter costume in the porters closet)
After you investigate the smudges on the luggage (and get scissors thrown at you), ask the Coal Man about it, and then verify his alibi with the Porter. When you return to the luggage car, the French lady reporter will suggest that you disguise yourself as the Porter. Go to the Porter's room and put on the extra uniform (at least the hat). Now Tesla will open the door for you.
You can get up via the open hatch in the baggage car.
cabbage!!
Although the porter throws away the order list, the writing has made an impression in the pad. Pick it up and use your pencil to shade the empty page, and you will find that Tesla ordered the prune juice.
Press the "customize" button at the top right corner of the screen. I think it's a green shirt...Or something like that. After you press it, click on the person whom's clothes you want to copy. Then just dress yourself :)
As you walk through the train you find a pencil. When the porter throws away the drink order, pick up her order pad and use the pencil to shade the blank page, to reveal any marks made on the next page. The orderer is revealed as Nikola Tesla.