Which character in "The Glass Menagerie" could be considered a tragic hero?

Tom is a tragic hero in The Glass Menagerie.  He is trapped in a situation that he cannot get out of, his position in the family as breadwinner. He can't get out of this situation without dramatically damaging his relationship with both his mother and his sister.  He is particularly flawed when it comes to his sister.  He is asked by his mother to bring home a gentleman caller for Laura.

Instead of really looking for someone who could actually go out with his sister, he just asks Jim to dinner, not realizing the Jim is engaged.  He sets up Laura for a dramatic disappointment that causes him to feel like a failure.  Even though he felt like a failure before the fiasco with the gentleman caller, he still went to work at the shoe factory, trapped in a job he hated.  He escapes the drudgery of this job by writing poetry while he is on the job. 

We both pity Tom for his stifling life with his mother and despise him for not having more ambition to really take care of his abandoned mother and crippled sister.

Tom is a character that evokes a sense of what might have been.  He definitely lets his pride get in the way of his success both with his family and with his ability to get ahead in life.

He despises his mother, and feels sorry for his sister.  He does not have a true relationship with either of them.