Do you like travelling by train?
I think travelling by train is good fun ! or,
I enjoy travelling by train because it's good fun !
" funny " = something that makes you laugh e.g. a comedy film./ telling jokes.
" having fun " = having a good time / enjoying yourself. e.g. going out with your friends.
" with train " = you travel BY car / train./ boat / air. ( in an aeroplane. )
oh thanks , I will careful for that rules that you said