What is the maximum speed when handling a multiple unit locomotive without cars?

The maximum speed when handling a multiple unit locomotive without cars is set at freight train speed, which is generally higher than the specific limits set for lightweight or more sensitive operations. This is based on standard operating procedures that allow for locomotives to operate at freight train speeds when they are not coupled with any additional railcars. The reasoning for this maximum speed is centered around the design and capabilities of multiple unit locomotives, which can safely handle the same speeds as freight trains while also following the regulations that govern their operation.

In contrast, the specific speed limits of 30 mph, 45 mph, and 50 mph are typically designated for other scenarios or operational parameters that involve different types of equipment or add an additional layer of safety and maneuverability. Therefore, these limits do not apply when a multiple unit locomotive is operating alone without any cars attached.