Obviously, any requirement as to valuation which would impose on the carrier such a result as that shown would compel the continuance of the less efficient service and prevent the progress which such replacements express. The railway business is a continuing one, and an improvement ought to be made whenever it can earn income, not only on its own cost, but on that of the property abandoned, even though it cannot afford income sufficient to wipe out the whole capital charge for the latter in a single year. There is no reason for requiring each item of capital to earn its cost in addition to its interest during its individual life. Such a requirement would cry halt to progress. It is reasonable and proper that such charges to operation should be made as far as the rapid development of the art of transportation permits, and such is the practice of every well-managed railway; but, to make the practice uniform and compulsory, permitting no exceptions and allowing no scope for individual judgment, is quite another thing. When the conditions warrant such a course, the railway ought to be permitted to adjust its accounts in a manner of which the following is typical: Replacing. Not replacing. Capital account $19,750 $5,000 Additional net operating income attributable to 1,000 250 this item Charge to operation for abandoned property 250 ______ _____ Operating gain $750 $250