Handbook of Railroad Construction; For the use of American engineers. / Containing the necessary rules, tables, and formulæ for the location, construction, equipment, and management of railroads, as built in the United States.

by George L. Vose

TIME TABLES.

Fig. 158, (see end of volume).

419. The most complete graphic solution of an engineering problem, is doubtless the time table of S. S. Post, Esq., chief engineer of the New York and Erie Railroad. Let the vertical lines represent time in spaces of ten minutes each, and the horizontals, distances, the heavy lines representing the several way stations. Suppose now that we leave station A at six, A. M., and wish to arrive at K at two, P. M., stopping ten minutes at each station; the number of way stations being eight, the whole time consumed in stops will be 10 × 8 = 80 minutes. From two, P. M., and on the line K, go back eighty minutes or to M, and from A draw A B, in the direction A M, which cuts the line B B at B, which is four miles, or thirteen minutes from A. Now, as we wait ten minutes, pass along on the line B B one division (ten minutes) to B′ and start again parallel to A B, arriving at C at one and a half hours from starting. Proceeding thus, we arrive at K at the required time. The inclination of the line shows the speed. Thus, if it passes twenty horizontal spaces in six vertical divisions, we have twenty miles in sixty minutes, or twenty miles per hour.

Suppose now we would start an express train at eight, A. M., from A to arrive at K at one, P. M., (see line 8 F,) it will pass the first train at station F, and will run at the rate of seventeen miles per hour from A to F, at the same rate from F to G, and at thirteen miles per hour from G to 1.

Suppose also that we start a train from K at six, A. M., to arrive at A at eleven, A. M., we pass the before-mentioned trains at E and D.

Also a freight train which is required to pass the above named trains, leaving K at eight, A. M., and arriving at A at one, P. M., will stop ten minutes at G, ten minutes at M, pass the first train at L, wait ten minutes on a siding at two and a half miles from L, and run to A at nearly a uniform rate of speed.

So also may the motion of any train be laid down and traced through the hours of the day upon the table. By plotting the profile of the road upon the line A K, the places are shown at which grades will oblige us to use a less speed. Curves also may be shown by increasing the steepness of the grades; or by making a grade on the profile when the road is level, steep enough to involve an amount of power equal to that consumed by the curve.