What speed must trains adhere to within joint track and time limits?

When trains operate within joint track and time limits, they must adhere to restricted speed. This requirement is in place to ensure the safety of all train movements, particularly in areas where multiple railroads share tracks or where there may be special operational conditions. Restricted speed is defined as a rate of speed that allows a train to stop within half the distance of visibility ahead. This limitation is critical in joint occupancy situations because it minimizes the risks associated with conflicts between trains and ensures that operators have enough time to react to any unexpected obstacles or conditions on the track. By enforcing restricted speed, railroads can mitigate potential hazards and enhance overall safety in shared rail environments.