Section 61. Whenever a town shall have purchased or taken real estate for payment of taxes the lien of the town on such real estate for all taxes assessed subsequently to the assessment for payment of which the estate was purchased or taken shall continue, and it shall be unnecessary for the town to take or sell said real estate for non-payment of said subsequent taxes, costs and interest; and on redemption from such taking or purchase, said subsequent taxes, costs and interest shall be paid to the town, and the payment shall be made a part of the terms of redemption, except that if any of the said subsequent taxes have not been certified by the collector to the treasurer to be added to the tax title account, then redemption may be made by payment only of the amount of the tax for which the estate was purchased or taken and of such subsequent taxes as shall have been so certified, together with costs and interest. The collector shall certify to the treasurer not later than September first of the year following that of their assessment all subsequent taxes which become part of the terms of redemption and the treasurer shall give him a certificate stating that the amount or amounts have been added to the tax title account or accounts and the collector shall be credited as if the tax had been paid in money. A city or town which has assigned a tax title held by it shall, after such assignment, have all the rights and powers to take or sell the real estate affected thereby, for the nonpayment of taxes, which it would have possessed had said city or town never been the holder of said tax title.