aspergers obsessive behaviour

My son is now 11 years old and has never been diagnosed with aspergers syndrome but the obsessive behaviour he has displayed over the years is manifesting itself from war of the worlds, cars and trucks and now the obsession has turned to trains.  He will talk about trains, tracks, engines, specific types of trains and knows all information on which year they were built, and has a photographic memory about the subject.  He will talk about trains CONSTANTLY and I feel this is very obsessive behaviour.  He will sit on youtube watching signal crossings for as long as i will let him and becomes upset if i hint at the fact that i am not interested in what he is saying.

The reason i have never taken my son to see a doctor regarding this is because the only symptoms he seems to display is the obsessive behaviour.  He is a very intelligent boy and has no problem with social circumstances, interacting with people or making friends.  He is a very popular boy and is well known for his manners and intelligent use of words when conversing. (sometimes i am surprised at some of the things he says)

I am now thinking this could be more of a OCD issue rather than aspergers due to the fact that he has no psycho social problems and did not display any symptoms of aspergers as a baby or young child eg:  rocking, use of speech eg ''baby talk'' and other symptoms.

If anyone could comment or help me with this i would be most grateful.
Thankyou for reading
Kelly

[JGF25]

To be honest with you, I'm not a doctor so I am not qualified to give any kind of diagnosis.  I will say that the obsessive part of OCD usually revolves around irrational thoughts.  Obsessive thoughts about ones health, harming others, catastrophizing thoughts, etc, and not so much an obsession with one thing in particular such as trains, or engines, etc.  

The compulsive component revolves around having to do a ritualistic action to alleviate an urge.  Such as counting, checking, etc. Not performing this ritual would result in anxiety for this person.  

So your question is a tough one for me.  If this were my child, I would definitely seek out a professional such as a psychologist that can diagnose his behaviors so that he can receive the proper treatment. I think what he has is an unanswered question mark and that "self-diagnosing" is probably not the best thing to do by either of us.  He may not have anything other than a brilliant inquisitive mind.  

My best.  

[JGF25]

The more I think about it, it would be worth you posting this on the ADHD forum.  Not that he has ADHD...we really don't know but Sandman2 will answer and he used to be a principal and teacher and he knows a lot about child behavior.

[SuperCake]

I have Asperger's myself.

At first, my obscessions drove my poor mother crazy.

they went like this.

Trucks
Aeroplanes
Trains
Video Games
Computers
Mobile Phone Hacking
Musical Equipment
C++ Programming

After a while, she learnt to switch off.. and just says things like "Very Good" or "Thats great!" even though it probably drives her up the wall.

These days though, she is asking me alot about computers :D