How many axles of dynamic braking are available on a consist with 4 SD-40 locomotives?

In a typical configuration, each SD-40 locomotive is equipped with 6 axles. When you have a consist of 4 SD-40 locomotives, you can calculate the total number of axles by multiplying the number of axles per locomotive by the number of locomotives.

6 axles per locomotive multiplied by 4 locomotives equals 24 axles. It's important to note that dynamic braking is primarily dependent on the axles equipped with traction motors, which in this case, all of the axles on the SD-40s are equipped to provide dynamic braking. Thus, the consist with 4 SD-40 locomotives indeed provides a total of 24 axles available for dynamic braking. This understanding is essential in train handling as it helps engineers gauge how effective the dynamic braking will be in slowing down or controlling the train.