Possessed to obsess.

I have this compulsive, obsessive personality disorder which drives me to sprout nonsense and babble on about random issues and bare embarrassing facts and say things without thinking or not really saying whatever I wanted to say in the first place and dodging questions which I know I want to answer.

I just can't stop thinking or waiting or thinking again.

It doesn't mean I'm already on another train or waiting to climb on board one. I just want to stay on the platform and watch the passing trains. Being here calms me down and makes me feel contented.