FREIGHT TRAIN PERFORMANCE

(Not including mixed, special, or motor car trains)

Month of MAY, 1919, compared with same month of previous year.

(A) Miles of road-miles of first running track. Miles other main tracks-miles of second, third, fourth, or other multiple running tracks, not including yard tracks and sidings.

(B) Follow "Classification of train miles, locomotive miles, and car miles," Interstate Commerce Commission, July 1, 1914. Include electric locomotive trains, but exclude mixed, special, and motor car trains. Train miles-Account 801, both ordinary and light; locomotive milesAccount 811; car-miles-Account 821. Where movement of traffic as a whole is not east and west, substitute north for east and south for west, or combine north and south with east and west according to traffic movement.

(C) Gross ton-miles-tons of 2,000 lbs. behind locomotive tender (cars, contents, and caboose) moved one mile; to be computed from conductors' train reports. Include electric locomotive trains, but exclude mixed, special, and motor car trains.

(D) Rating_ton-miles-the potential gross ton-miles which would have been produced had all trains been loaded to 100% of the slow freight rating for normal weather conditions, taking account of changes in rating over sections of the run. When the potential train load in the direction of favoring grades is now expressed in number of cars an arbitrary tonnage rating should be used as the basis for Item 6.

(E) Net ton miles-tons of revenue and nonrevenue freight moved one mile; to be computed from the conductors' train reports.

(F) Train hours-the elapsed time of trains between the time of leaving initial terminals and time of arrival at final terminals, including delays on the road. May be taken from conductors' train reports or dispatchers' train sheets.

the westward direction there is an increase of 19.4%. Both the car-load and the percentage of loaded cars have a material effect on the car-load, as it is possible to handle a greater gross traintonnage, in heavily loaded cars with few empty cars, than in lightly loaded cars with a large proportion of empties. The unit resistance (per ton) of an empty car is approximately twice as great as that of a car loaded to its weight capacity. A locomotive on a given run may be able to haul 3,000 gross tons in fully loaded coal cars, yet be unable to haul more than 2,400 gross tons of empty or very lightly loaded cars.

Attention may next be directed to the net tonmile so as to see the relation between the paying load and the gross load of the train. It is noted that the net ton-miles show a decrease of 25.3%, the loss being much greater eastward. As the loss in gross ton-miles is 20.4%, it is plain that the net ton-miles this year bear a lower percentage to gross. The details are shown in Item 13. The loss was altogether in eastward movement. Its per cent of net to gross is 6.5% less than last year, while the westward movement shows an increase of 1.7%, the combined unit showing a loss of 6.2%.

Now, we may examine the effect of the time element. Train-hours show a decrease of 25.8%, while train-miles show a decrease of 29.0%. This indicates a loss in train-speed. Item 10 shows the extent of the loss-4.3% decrease in miles per hour. The decrease is greater in the westward direction.

The combined effect of changes in gross trainload and speed is shown in the gross ton-miles per train-hour. In this case there is a gain in one factor and a loss in the other factor. The gross train-load shows an increase of 12.2%; the train speed shows a decrease of 4.3%. The gain in the load was sufficient to offset the loss in the speed, consequently we find an increase of 7.4% in gross ton-miles per train-hour.

Finally, we may turn to the unit which is the net result of those already discussed-the net ton-miles per train-hour. The figures show a slight improvement-an increase of 0.7%. The eastward performance shows a loss of 0.8%, but the westward performance reflects a gain of 15.7%. The relatively small gain in net ton-miles per train-hour, compared with gross ton-miles per train-hour, is due to the lower ratio of total net ton-miles to total gross ton-miles. And, as already stated, this is due to a smaller car-load, although the loss in that factor is lessened by a relatively smaller gain in the per cent of loaded to total car-miles.

The foregoing comments are intended merely to be suggestive. No two persons will follow the same order in undertaking an analysis of the figures. It is plain, however, that whether we proceed from the basic data to the final inclusive unit, or work backward from that unit, it is easy to trace the effect of the changes in each factor, and to proceed with intelligent inquiries designed to bring out the reasons for the relatively poorer performance in the one direction. The statistics on this form should, of course, be compared with