I'm sure this image defies the laws of physics (the blur is ahead of the train). Therefore, this is an experimental shot where the laws of physics do not apply. I remember when I was in school and someone shot an experimental video I was always confused about how to critique it. They could be very abstract and so I wasn't sure what meaning they were trying to put across. Typically, I just said, "it was interesting." Sort of like the movie Brazil. I must have seen it 3 times and I'm still not sure what it was about (but it was interesting).
My goal was to take this photo with camera settings that would blur the train. However, I didn't set the settings correctly so the train was clear and looked as if it was stopped on the tracks. Since this is a commuter rail train I only had the one chance to capture the shot. I would have had to wait another two hours for the next outbound train (weekend schedule). I felt the image needed something so I decided to experiment in Photoshop. In Scott Kelby's Lightroom book he demonstrates how to add this blur effect.
Personally, I think the blur helps the image. But everyone's tastes are different so this may not work for others. I'm realizing more and more, that for me, it's not as much about the final image as it is about the experience. I was happy to actually be outside and using the camera again and then being able to experiment in Photoshop and having fun with it.