Section 56. The selectmen and all boards, committees, heads of departments and officers authorized to expend money shall approve and transmit to the town accountant as often as once each month all bills, drafts, orders and pay rolls chargeable to the respective appropriations of which they have the expenditure. Such approval shall be given only after an examination to determine that the charges are correct and that the goods, materials or services charged for were ordered and that such goods and materials were delivered and that the services were actually rendered to or for the town as the case may be; provided, however, that such approval may be given to any bill received from a state agency for the town's share of the costs of a federal urban planning assistance program, established under the provisions of section 701 of Public Law 83?560, as amended, before any goods, materials or services ordered or to be ordered under such a program have been delivered or actually rendered, as the case may be. The town accountant shall examine all such bills, drafts, orders and pay rolls, and, if found correct and approved as herein provided, shall draw a warrant upon the treasury for the payment of the same, and the treasurer shall pay no money from the treasury except upon such warrant approved by the selectmen. If there is a failure to elect or a vacancy occurs in the office of selectman, the remaining selectman or selectmen, together with the town clerk, may approve such warrant. The town accountant may disallow and refuse to approve for payment, in whole or in part, any claim as fraudulent, unlawful or excessive, and in such case he shall file with the town treasurer a written statement of the reasons for such refusal. The treasurer shall not pay any claim or bill so disallowed by the town accountant. So far as apt this section shall apply to cities.