The case is similar to that of a locomotive: When new, it is kept in the vicinity of the shops, because trouble from lack of proper adjustment and weak parts is likely to develop, and the maintenance charges may be much higher than a few months later when the machine has "found itself" and, as an operating machine, is more efficient than when new. However, no one will insist that it has an added physical value in dollars and cents, or that the excess cost of repairs and maintenance during its early life should be added to its cost of reproduction now; in fact, it is a second-hand machine, and the maintenance charges must be paid for out of its use. Generally, when a roadbed is turned over to the operating department by the construction department, it is in good line and surface, and if an appraisal were made at that time its condition would be 100%; but as soon as it is placed under traffic, it begins to depreciate, as shown by the fact that it requires constant attention to keep it up. If the roadbed is cross-sectioned at each station and actual quantities calculated from cross-section notes, there would be no depreciation, but if the grading quantities are calculated from profiles of the line, as constructed some time previously, and for a standard width of sub-grade, with a percentage added for shrinkage, and allowance made where banks have been widened, etc., it will probably be found to exceed the actual measured quantities, because the action of the elements in washing the slopes, the wearing of the shoulders of the embankment due to foot traffic, etc., will show some depreciation in quantities. It is common practice to carry the item for grading over to the present-value column at 100%, or, with no depreciation. This practice, together with the present condition of the ballast due to maintenance, and that part of contingencies which covers washing of slopes, filling of ditches, sink holes, etc., certainly takes care of all adaptation and solidification which should enter into a valuation of physical property.