No engine brake on the KIHA 31

[Ryan Young]

According to the Microsoft Train Simulator manual (https://manualsbrain.com/en/manuals/1879724/?page=31) and the Procedures tab in the Help window, the KIHA 31 should have an engine brake that allows it to maintain speed on a descending grade. In MSTS, the key to activate this control is apparently the "P" key. This feature is not present in Open Rails, and our documentation mistakes the independent/locomotive brake ("["/"]" keys) for the "engine brake."