Roy,

I suspect that you may be out of luck, as the website reports that a minimum of 4" clearance is needed. However, I've found that Amtrak does sometimes push the requirements that is listed on the site. For example my brother-in-law was able to get an Expedition that slightly exceeded the width noted on the site onto the train without trouble.

I strongly suggest that you call 1-877-754-7495, which is the direct line for the Auto Train staff. They, unlike the staff at the normal Amtrak toll free number, are better trained regarding the sizes and types of vehicles that the Auto Train can handle. They are the definative source.