What is the speed restriction for trains operating in Release mode?

In Release mode, trains are required to operate at a substantially reduced speed, specifically below 12 mph. This speed restriction is implemented primarily to ensure safety, particularly when the normal controls of the train may not be functioning, and there is a need for caution in movements. Operating under this limited speed helps mitigate risks of accidents or collisions when traction or braking systems are not fully operational.

The other options suggest higher speeds that would not align with the safety protocols established for Release mode. Unlimited speed based on signals would imply a risk that is not permissible in this mode, while speeds under 25 mph and adhering to local speed limits could still be too fast for the conditions present during Release mode operations. Overall, the focus is on maintaining the lowest safe speed to ensure the well-being of both the train and any surrounding entities.