The Dynograph Car

International Tract and Missionary Society · Oakland, California · Jan 1, 1885

The Dynograph Car.

THE car perfected by P. H. Dudley for automatic or mechanical inspection of railroad tracks is very ingenious. By delicate machinery connected with the axle of the car by belts or cogs, every vibration, tilt, or perpendicular variation in the position of the car is noted on paper with pens set for the purpose, and the record thus made is reduced on paper by the expert in charge, who thus far has been Mr. Dudley himself. Thus a complete and accurate chart of the track in profile and alignment may be submitted to the section superintendents, showing not only the amount and kind of work required to perfect the road, but also the precise places referred to mile posts on the road where the work should be done. The registration of these machines is so perfect that Mr. Dudley can, if the rails are comparatively new, tell when passing at the rate of twenty miles an hour over a railroad what mills rolled the rails on which he is riding, and knows at once when passing from rails of one manufacturer to those rolled by a different maker. From the record thus made Mr. Dudley makes up a profile map of the road, which, by curved lines, shows, on a scale of one-fourth of an inch to the mile, the following things: First, any irregularities of gauge along the line; second, defects in horizontal alignment of the rails; third, the grades along the railroad; fourth, the condition of the track at any point, compared with a perfect track; fifth, whether and how much the track can be improved by labor, or whether new rails alone are needed to make it more perfect; sixth, the brand and kind of rails used on each mile of road; seventh, the number of years each rail has been in place, and, eighth, the comparative percentage of tangents and curves per mile of road. This map completed costs $2.50 per mile, the high price coming mainly from the immense amount of work required to interpret the results and the delicacy and cost of the instruments used in the work. Mr. Dudley is the inventor of all his instruments, and inspects each year from 6,000 to 10,000 miles of track, living on his car during these trips. From 3,000 to 5,000 "miles" of paper are kept in the car constantly, and fifteen gallons of ink per 100 miles of track are used in "spotting" low places.—Evening Post.