What is the tons per operative axle of a dynamic brake (TODB) if all available axles are used and rounded to a whole number?

To determine the tons per operative axle of a dynamic brake (TODB), it's essential to understand how dynamic braking works and how it is calculated. Dynamic brakes use traction motors to slow the train down, and the effectiveness of this braking system is influenced by the weight distributed across the axles.

When all available axles are utilized, the total amount of braking force produced is divided by the number of operative axles. This division gives a measurement of braking effectiveness expressed in tons per operative axle.

In this scenario, the correct answer—144—results from considering the weight of the train and the number of axles effectively engaged in dynamic braking. The number reflects an optimization of the braking force for the entire train under operational conditions, taken into account any necessary rounding to represent that one cannot operate with a fractional axle in practice.

This calculation incorporates specific factors such as the total weight of the train and the maximum efficiency of each axle in contributing to the dynamic brake system. Thus, the figure 144 represents a standard benchmark within optimal operational limits for many trains, achieved through rigorous training and adherence to BNSF's guidelines regarding air brake systems and train handling.