To increase, from time to time, its capital stock, but never to exceed the amounts actually expended by the railroad company in constructions, completions, equipments, and additions to its railroad and property; a stockholder shall not be liable for the debts of the corporation beyond the sum due for unpaid subscriptions.To issue preferred stock and fix the face value of each share at such amount as shall be determined by the board of directors, for the purpose of satisfying, paying and retiring the outstanding bonds, notes, secured or unsecured, or any other evidence of obligations of any kind or character, which obligations have been or shall be incurred by the railroad corporation.Codes, 1892, § 3581; 1906, § 4083; Hemingway's 1917, § 6712; 1930, § 6076; 1942, § 7727; Laws, 1938, ch. 347.