Earl,
We looked at a lot of photos and there are plenty of times when the tank cars were anywhere from one to five or six cars back in the train. When it was a solid block of 10 or 12 tanks, they were right behind the engine but when there were only a few, it didn't seem to matter. Since we only had 4 tanks to work with and were going to have them at the front of the train on the return trip from Antonito, we decided to mix things up a bit. Take a look at some of John West's photos. Here's an example.
Cumbres Turn
Michael Allen