Upon any application for authority to issue securities for the purpose of providing funds for discharging any indebtedness incurred by a common carrier by rail in good faith prior to July 1, 1914, in acquiring property, or for other lawful corporate purpose, no deduction shall be made from the cost thereof, as determined by the department, on account of any estimated depreciation of plant and properties beyond the portion, if any, of such cost which it may appear has been paid out of the depreciation reserve of said common carrier by rail, if any, or out of earnings, to make good depreciation.