periods of operation one must necessarily compile cost data for two lines of railroad which the length and physical conditions are essentially similar. The new lines should be compared with a line which has been in operation under similar traffic for a period of several years and where the track and roadbed have become fairly stabilized.

The physical and topographic conditions vary so greatly in different parts of the country that this is a subject which has to be approached with a great deal of care as in many places it would be difficult to find two lines of railroad which are closely comparable.

When determining the difference in cost of maintenance during the early period of operation of one line with another, one should also take great pains to see that the methods and standards followed in construction are approximately identical. One should not attempt to compare a line built for Class A, main line traffic, and one built to handle secondary or branch line traffic.

If the natural surface and the soil is of a stable nature one would be lead to expect that if the new roadbed were well built that the early cost of maintenance due to the solidification of the roadbed would not be excessive. However, a comparative study might introduce either elements which would make a change.

A number of railroads have been compiling data in order to develop this information but their study has not as yet reached a concrete form. For the consideration of the members of the Association we are submitting Forms "A" and "B," which may prove of value in a study of the subject.

The methods now in vogue on different railroads in compiling cost of maintenance in compliance with the instructions of the Interstate Commerce Commission are of sufficient extent to enable one to arrive at a correct result, provided these methods are followed intelligently.

Main or Branch.

State.

Characteristics of Line:

Topography of Country Traversed:

Soil:

Temperature range...... ..to.

yds...

Other materials, cu. yds..

To the American Railway Engineering Association:

Your Committee on Economics of Railway Location reports progress on the subjects assigned to it, as follows:

(1) Revision of Manual

No changes in the Manual are proposed at this time.

(2) Effect of Curvature on Cost of

(a) Maintenance of Way, and
(b) Equipment

The Committee has reached the conclusion that it is difficult to present information on this subject that would be of practical value. It would be possible to work out results for a larger number of factors at the end of extended research, tests and experiments; but the practical value of such results would be doubtful. It would be practically impossible to reconcile the conclusions that might be reached with the practical conditions of operation. For these reasons, it is the recommendation of the Committee that this subject be dropped.

(5) Study and Revise to Date the Subject of Railway Locomotive Power

The Sub-Committee assigned to this subject is making a study of locomotive tractive effort and the various processes proposed for predicting tractive effort at various speeds, in the expectation of revising the present section on "power" in the Manual, where necessary. When conclusions concerning methods for estimating tractive effort have been arrived at, it is the purpose of the Sub-Committee to test their correctness by comparing calculated tractive effort with the tractive effort actually attained in service, determining the latter by means of a dynamometer car. This work could not be completed in time for presentation with this report. It is therefore recommended that the subject be continued for the ensuing year.