RULE 4. SHORT TURN-AROUND SERVICE, Engineers on short turn-around passenger runs, no single trip of which exceeds 80 miles, including suburban and branch line service, shall be paid overtime for all time actually on duty, or held for duty, in excess of 8 hours (computed on each run from the time required to report for duty to the end of that run) within 9 consecutive hours; and also for all time in excess of 9 consecutive hours computed continuously from the time first required to report to the final release at the end of the last run. Time shall be counted as continuous service in all cases where the interval of release from duty at any point does not exceed one hour. This rule applies regardless of mileage made. For calculating overtime under this rule the management may designate the initial trip. Overtime in short turn-around passenger service will be paid for at the hourly rate of one-eighth the daily rate on the minute basis.