Comment 1 for bug 1393270

Locomotive chuffing volume is controlled by the following formula, it is proportional to the effort the engine puts up at a time:

Variable2 = Math.Min(CylinderPressurePSI / MaxBoilerPressurePSI * 100f, 100f);

This variable is closely related to the actual steam locomotive physics calculations. In MSTS the steam physics is completely different, and probably partly broken. Thus replicating the behavior here is nearly impossible. This was discussed on ET, and based on the discussion I would mark this bug report as "Won't fix" status.