Would your parents let you do this ?

I'm going to ask my parents if I can catch the train up to Newcastle from wales with my friend tomorrow to go and visit another friend ! The journey is 4hrs long and i've done it before, however, things didn't really go to plan last time ! However, what i'm asking is whether you think there's a good chance i'll be allowed to go ! My friend i'm going with is very safe and takes care of me and he's going to visit Newcastle university whilst I stay with my other friend. I really want to go ! How do you think I should go about asking my parents about it ? Thanks x