Final answer:
Train operators are required to read and sign special orders when there are important changes to standard operating procedures.
Step-by-step explanation:
Train operators are most likely required to read and sign individual copies of a special order when there are important changes or updates to standard operating procedures.
These special orders typically cover critical information such as changes in train routes, schedules, or safety protocols. By signing and filing the order, train operators acknowledge their understanding and agreement with the changes.