Re: battlefield 3 single player on pc. I am new to playing games is campaign how to play single player? My space bar does not let me climb up side of train why?

Try using the "W" key, it is the key used to climb ladders, I believe that the space bar is used in the campaign mission to jump from hand hold to hand hold on the side of the train but "W" is used to move up the side of the train.