hmm, im not sure how tight train security is, but i would say, if you could bye a coca-cola bottle that is used for stashing shit, they sell them for 20 bucks at a smokers store here in my town, and u could stash anything from .5 g to 2 oz. in it. and keep it in your bag, be warned, if you have a larger amount double or tripple bag it. thats what i would do anway