Poor Old TC...

At least here in the midwest, and I think it applies all over, you can only double tow with a fifth wheel primary. Think about it the fifth wheel has much more tounge weight, so it can handle the extra load on the back bumper. A normal bumper pull will get a teeter totter effect on the center unit from the rear unit. The whole set up pictured looks like something to be avoided. I wonder how many of those axels have live braking.