It may be good business to store the plant at some point (as at the nearest railroad station) that it must pass through to become available anywhere, and hold it for prospective adjacent work.
On the other hand, if surrounded by centers of supply or an abundance of other second-hand plant, if little new work is being let, or if it is desired to make a quick sale, a very much lower percentage of original cost will be realized.
On page 133 in discussing the use of hydro-electric power, a possibility was suggested which should not be lost sight of, i.e., the continued use of portions of the plant, at the same location, as a permanent feature of the project or under the changed conditions created by the project. In such a case, as also in the case of any important highway or railroad built primarily to furnish access to the work, it is probable that this adaptation to permanent future conditions would have been contemplated by the promoters or builders of the project. If so, it would have influenced the financing of the project and the conditions of the construction contracts. In addition to features so broad and prominent as to have been considered in the original conception of the project, others might be found adaptable or necessary to the new or unforeseen conditions prevailing after completion of the work. Thus a small remaining community might make use of buildings, water supply, sewerage or lighting systems, refrigerating machinery, second-hand lumber, etc.
The foregoing considerations, however, can seldom be applied to any estimate of plant charge at the time (before the work is started) when such estimate must be made. Conditions two, three, or five years hence cannot be conjectured for such a purpose. The only course is to estimate the cost of getting it to a point of probable demand, and its sale value at that point. If circumstances happen to be such that the plant sells for more or less than the estimate then the difference is chargeable respectively to profit or loss upon the work. Obviously certain pieces of machinery have depreciated much less than certain others. Thus an engine, generator or air compressor which has been set on a good foundation, housed and cared for by intelligent operators will be worth a larger percentage of its original cost than other items as dump cars, concrete mixers, drills, rollers, scrapers, carts, etc., which have suffered the casualties incident to rougher contact with the work and the workmen. Certain portions of the plant as buildings are worth nothing for removal but may have some value if they can be used as buildings on the same location; or if they must be removed they may have a small value in the immediate locality as buildings or lumber. Other portions of the material or works charged originally as plant have no value at all. In fact, they are a liability to the extent of the cost of their removal in order to comply with the usual requirements for clearing up the grounds.