Road train vehicles have been applied as one of the common and efficient ways for transportation of goods, specifically hazardous liquid cargos, in different nations. These vehicles have a wide variety of lengths and towing systems such as the fifth wheel or the dolly draw-bar. Based upon specific regulations, they could be authorized to move on specific roads. In order to avoid hazard and danger in case of accidents, safety performance of a B-train vehicle as a specific type of road train vehicles is investigated in this paper. A Multi-Body Dynamic (MBD) model, which consists of a prime mover and two trailers coupled by fifth wheels, are simulated in the initial phase of the study. The developed dynamic model is capable of simulating required tests as well as the SAE lane change, along with a constant radius turn for the purpose of roll and yaw stability analysis and safety evaluation. The effects of variation of the fluid fill level are considered in this research. The trammel pendulum concept is adopted for simulation of fluid movements, known as sloshing, in two articulated tankers of the model. Moreover, a preview driver controller is integrated to the MBD model to provide the follow-up the path during the lane-change and constant radius turn maneuvers. Compared to the results from the simulation of fixed liquid cargo, the critical behavior of the vehicle in terms of rollover at lower speeds is observed when the movement of fluid is taken into account. The results show that transportation of a high density fluid yields a more critical condition compared to a low density one, when the same axle load is retained.