Abstract: Through the simplified mechanical model of DF8B diesel locomotive radial bogie,the formula of coupling rod’s loads can be deduced.In the straight track condition with different train speed,the result of simulation and test can be got respectively by the simulator software SIMPACK and real vehicle test.Through contrasting the theoretical value,simulated value and test value of the loads of the coupling rod of the bogie,the accuracy of theoretical derivation has be verified.With the conclusion of the analysis,the factors affecting the coupling rod’s loads in the straight condition are founded and the result provides a theoretical basis to the radial bogie further improve.

Key words: DF8B diesel locomotive, radial bogie, mechanical model, straight track conditions, coupling rod