In contrast to the above, baggage and express are very generally hauled in the same and a much lighter and less costly car than the mail car, and increase in tonnage is accommodated by hauling greater loads per car. In the case of freight, increased density means larger car and train loads and greatly reduced costs of operating per ton mile. Despite these differences in conditions, the automatic scale has secured to the Government a larger reduction in mail rates per ton mile in the last ten years than the percentage of fall in freight rates, despite higher labor and material costs of railroad operating. As a result, the mail business--which, according to evidence introduced before the Congressional Committee of 1899, was unprofitable at that time, has been made more unprofitable at the present time by the heavy rate reductions of 1906-7. As the greatest reduction made deals with mail routes on which traffic is heaviest, a consideration should be given to the following conditions of handling mail on such routes: HEAVY TRAFFIC MAIL ROUTES. On very many of the heavy traffic routes where the principal reduction in pay occurred a large part of the mail is now handled in special mail trains run at excessively high rates of speed. Such trains introduce the following conditions: 1. A very much greater liability to accident. A large proportion of the deplorable accidents that have occurred on the American railroads in recent years have occurred to excessively high speed trains, accidents to such trains being almost invariably destructive to life and property. An examination of serious accidents on the Union Pacific System and Southern Pacific Company for the calendar year 1906 shows that 36 per cent. of the property damage from all causes, including negligence, as traceable to trains not under control and excessive speed, whilst 30 per cent. additional damage was due to causes that might prevent inferior trains getting out of their way, such as keeping main line on time of superior trains, failure to observe signals or orders, etc. 2. Mail trains run at excessive high speed are much more expensive to operate than other trains, for the following reasons: (_a_) Fuel consumption per traffic unit is very much greater at high speed because of diminished tractive power of locomotives. (_b_) A relative greater hauling capacity of locomotives must be consumed in moving trains at higher speeds. (_c_) Excessive speed requires higher standards of track maintenance, double-tracking, block signals, heavy rail, better ballasted roadbed, etc., etc. (_d_) High speed means increased wear and tear on equipment and track. (_e_) High speed trains are expensive, delaying and adding to the cost of other traffic.