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Gross Ton Miles Per Train Hour
A Measure of Performance

Speaking recently at the annual convention held in Chicago of the Travelling Engineer's Association Mr. S. O. Dunn, editor of the “Railway Age,” said:—

“The principal function of locomotives on our railways is to haul freight. Probably the best measure of their performance is the number of gross tons hauled one mile per train hour. This formula takes account of the weight of the cars and of the freight that is hauled, and also of the speed at which they are hauled.

“It would appear that gross tons per train in 1906 averaged 881 tons and in 1916 about 1,249 tons. This was a period during which the railways put forth great efforts to effect economies by increasing the average load of freight trains, but did little to increase their average speed. It seems reasonable, therefore, to assume that in both 1906 and 1916 the average speed of freight trains was 10 miles. On that assumption the increase in average gross ton miles per train hour between these years was about 42 per cent. The increase in the gross train load between 1916 and 1925 was from about 1,249 tons to 1,670 tons, or 34 per cent. The increase during this period in the efficiency with which locomotives were utilised in road service cannot, however, be measured merely by the increase in the average train load. Since the passage of the Adamson Act, and especially since the application of punitive overtime in train service, the railways have made great efforts to increase the average speed of trains, and it was increased from about 10 miles an hour in 1916 to 11.8 miles an hour in 1925. The resultant of the increases in the average train load and in average speed was an increase in gross ton miles per train hour from about 12,490 in 1916 to 19,679 in 1925, or 57 per cent.

“These estimated increases of 42 per cent. between 1906 and 1916, and of 57 per cent, between 1916 and 1925 in gross ton miles per train hour are, of course, attributable, first, to improvements in locomotives and increases in their tractive power, and, secondly, to improvements in other railway physical facilities and in operating methods resulting in better locomotive utilisation.

“Gross ton miles per train hour have continued to increase this year, having in the first six months of 1926 averaged 20,196, or 5 per cent. more than in the first half of 1925, and 62 per cent. more than ten years ago.

“It is an interesting fact that while the average tractive power of all locomotives increased less in proportion during the last decade than during the preceding decade, the amount of transportation produced hourly by the average freight locomotive increased more in proportion in the last decade than in the preceding one. The explanation undoubtedly is that the locomotives placed in service within recent years have shown more improvement than those installed in the preceding decade, and also that much more attention has been given within recent years to means of increasing locomotive utilisation, the result being that the improved locomotive has been given a better chance to show what it can do……

“Only one-third of the locomotives now in service have been installed during the last ten years and only about 18 per cent. of them have been installed since 1920. Nevertheless, the increase in average gross ton miles per train hour since 1920 has been 36 per cent. while the reduction in the amount of coal consumed per 1,000 gross ton miles meantime has been about 16 per cent. There can be no doubt that the great improvement in operating results within recent years has been made possible largely by improved locomotives that have been installed within the last decade, and especially since 1920.

“We who follow progress in the fields of locomotive development and railway operation without participating in them have been witnesses of a general rivalry between those on the one hand, who develop specialities for locomotives and design and build them and those, on the other hand, who operate them on the railways. We have seen the former achieve rapid progress in improving locomotives. We have seen railway operating officers initiate new methods of getting more and better work out of locomotives. Both have been contributing to the marked increases that have occurred in the efficiency of railway operation and service. It seems not visionary to express the belief, in view of past experience, and especially that of recent years, that old locomotives may in future be more rapidly replaced with ‘the locomotive of to-day’ and that methods of locomotive utilisation may be still further improved, with the result of effecting in future much greater proportionate increases in efficiency of operation and improvements of service than even those that have been accomplished during the last five years.”