Section 189. Every railroad corporation issuing mileage tickets shall, upon presentation of such a ticket by a passenger, detach therefrom one coupon and no more for each mile and fraction thereof actually traveled; provided, that for distances less than three miles three coupons may so be detached. Distances to or from the station known as Back Bay on the New York, New Haven and Hartford railroad, and the stations known as Trinity Place and Huntington Avenue on the Boston and Albany railroad, shall be computed as if to or from the Boston terminal station.