All US multiple trailer combinations use semi trailers and converter dollys. Some western states also have truck, converter & semi-trailer setups too.

The one combination allowed everywhere is two 'pup' 24 - 28 foot semi-trailers w/ a converer dolly.

Canadians use B Trains where the front trailer has an extended frame that includes the 5th wheel for the 2nd trailer instead of a converter.

[QUOTE=wis bang;2552046. Some western states also have truck, converter & semi-trailer setups too./QUOTE]


This setup has been used for years around the gasoline business. However, it's known as a truck and trailer and it's just a little different that what you say. It's a truck then hooked to the truck by way of a drawbar. There's no converter gear so it is different when you hook and unhook. The turn table under the trailer is permanently mounted so you always unhook at the truck. It's rerally a sweet setup when you have to get into tight spaces and is not hard to back at all. I have seen a set up like you're saying but never with gasoline on, mostly hot tar. I would also think they would be a bear to back since you add another pivot point. The truck shown in my Avatar is a truck and trailer and is 85' long.

The length limit in states that allow it is 106'. This can be 2 45'ers or 3 28'ers. No limit on axles. Exceptions would be OD loads (over dimension) with permits.