Section 67. A railroad corporation may become an associate under chapter one hundred and fifty-six in the formation of a corporation for the purpose of erecting and operating a grain elevator within the commonwealth, and may take stock in any elevator corporation so organized, and, at all meetings, and in all transactions of such elevator corporation, the president of the railroad corporation, or in his absence any officer appointed by its board of directors, may represent, act and vote in the name of such railroad corporation.