§ 602. Expenses of sheriff for transporting prisoners. For conveying a prisoner or prisoners to a state prison from the county prison, the sheriff or person having charge of the same shall be reimbursed for the amount of expenses actually and necessarily incurred by him for railroad fare or cost of other transportation and for cost of maintenance of himself and each prisoner in going to the prison, and for his railroad fare or other cost of transportation in returning home, and cost of his maintenance while so returning. The county shall be reimbursed for a portion of the salary of such sheriff or person for the period, not to exceed thirty-six hours, from the commencement of transportation from the county prison to the return of such sheriff or person to the county prison, the amount of such reimbursement to be computed by adding to the amount of such salary the total amount of the aforesaid expenses incurred for transportation and maintenance and reducing the resulting aggregate amount, first, by fifty per centum of such aggregate amount and, second, by the total amount of the aforesaid expenses incurred for transportation and maintenance.