# How to calculate the maximum starting traction force for a train with multiple carriages?

Suppose I have a convoy composed of the following elements:

• A locomotive with 4 driven wheelsets (2 wheels per wheelset and therefore 8 wheels).
• $$n$$ carriages with 2 wheelsets each.

Assuming the weight is uniformly distributed on the wheels, from my understanding the maximum force that can be applied by the locomotive avoiding wheels slipping is given by:

$$F_{max} = m_{locomotive} g \mu$$

Where $$\mu$$ is the adhesion coefficient.

The point is that I'm not sure if I should consider also the passenger carriers and if not, then why. I think I should not consider them since the force that prevents the locomotive's wheels from slipping is just its own weight.

Furthermore, what if the locomotive had only 6 driven wheels out of the 8? Would that change anything?

In that case I think I should multiply the $$F_{max}$$ obtained by 6/8 am I correct?