Military trains are not new, I remember seeing them as a kid 30 years ago. No, I do not see this as strange at all. Its an effective way to move equipment from one point to another. I saw a lot of Styker AFVs and M1117s. For what its worth the Department of Defense have a really large fleet of rail cars all you have to do is look for the DODX reporting markings. If they have them, might has well use them.