The presented research is aimed at the derivation of a mathematical model of diesel-mechanical drivetrain of a rail vehicle. It is derived by means of the Lagrange’s equations of the second kind. The derived mathematical model allows to understand the essential principle of the derivation of the mathematical model of the diesel-mechanical drivetrain of a rail vehicle, an application of the numerical mathematical methods for the solving the equations of motion and for evaluation of the wanted outputs quantities, such as waveforms of revolutions and torques of shafts and others.
