From the lower flange of a suspended !; runway, made of a single I section, run wheels, from the axles of which the transporter is suspended.
In whatever form energy is produced and distributed to the train it ultimately appears as mechanical energy applied to turn one or more axles against the resistance to their rotation imposed by the weight on the wheels and the motion of the train.
If the energy supplied is distributed between several axles the relation becomes l l 2 3 w 3.
= RV (2) where T 1, T2, T3, &c. are the torques on the axles whose respective angular velocities are wl,w2, W3, &c.
The fundamental condition governing the design of all tractive machinery is that the wheels belonging to the axles to which torque is applied shall roll along the rails without slipping, and exert a tractive force on the train.