Double Trailer v3.1 by Siebel3D (v1.6.x)

Double Trailer v3.1 by Siebel3D (v1.6.x) for American Truck Simulator game.

Features trailer:

- Standalone
- Ai traffic
- Advanced coupling
- Animation brake
- Liftaxles

- double trailer

- detailed model 

Changes in v3.1:

- fixed errors

Tested  on game version 1.6.x