Itn regards to the Shed and the train, the train I believe around 14 feet of clearance. Remember, the train tracks are 2 feet below the surrounding terrain, so even with the 12 feet of the train tracks accounted for, that doesn't explain the drop off from 22 to 12 feet.
Second with the guessing of the shed, do you really expect the park to say whether we made a correct guess? Honestly, the park won't confirm or deny anything regarding the shed, besides the fact there will be a shed on Mystic Timbers.