First of all, not boring.

YOu have been depressed for a while, is there something, a certain event in your head, that may have started it?

To me the girl seem to be someone you love. but that person left you. you chased after that person, but lost your grasp on yourself while doing so. no you are trapped not knowing where to go. And then you came at peace with yourself.

so in the dream, the train was you. the girl was a part of your heart. you chased after her when she left, loosing yourself in the process.

but in the end it made you happy?

maybe your dream is trying to show you a light at the end of the tunnel. your subconscious is telling you that things are not nearly as bad as they seem. when life gives you lemons...

taking a Freudian approach, this dream is simply expressing your wish for something good to come out of all of your hardships.

Hope that helped and didnt just sound like rambling nonsense!

HUGS!!!

ps- YOU ARE IMPORTANT!!!!!!!