What is the maximum authorized speed for a light locomotive consist of two or more units?

The maximum authorized speed for a light locomotive consist of two or more units is 50 MPH. This speed limit is established for safety reasons, as operating at higher speeds can pose risks in terms of handling, braking distance, and overall stability of the light locomotives, which are often not fully loaded. Light locomotives are typically used in situations where weight is not sufficient to have a heavier consist, hence the specific speed regulation designed to ensure safe operations in various conditions.

The other choices represent speeds that do not comply with the regulations governing light locomotive operations, which define 50 MPH as the upper limit for safe transit under those conditions. Understanding these speed limits is critical for maintaining safety on the railways and ensuring that operational practices align with regulatory standards.