When it is necessary for the county school administrator to travel on business of the county, he or she shall be allowed mileage at the rate allowed by the provisions of section 81-1176 for each mile actually and necessarily traveled by the most direct route if the trip or trips are made by automobile, but if travel by rail or bus is economical and practical, he or she shall be allowed only the actual cost of rail or bus transportation upon the presentation of the bill for the same accompanied by a proper voucher to the county board of his or her county in like manner as is provided for as to all other claims against the county.