PREFACE. I AM publishing the following notes because I think they may possibly supply the want of a Field-book,-a want which I have often felt myself and have often heard expressedwhich, while avoiding as much as possible the intricacies of mathematics, would be of more general application than any of the books of this class which I have as yet come across. The Railroad engineer is rarely an expert mathematician in fnct it has always seemed to me that the time which must necessarily be spent by him in attaining mathematical proficiency might be very much better employed in reading up some of the more practical subjects of his profbssion. Bear-. ing this in mind, I have endeavored to strip the following pages of all unnecessary mathematical deductions, making it mainly my object to give the results deduced, and yet at the same time giving sufficient explanation to enable any one possessed of the ordinary smattering of mathematics and me chanics to deduce the same results for himself. I have avoided the insertion of Logarithmic Tables. I am well aware that to some this will appear a serious omission but considering that this is merely a Field-boolr, and not a work to be consulted in cases where accuracy in the 6th figure is ustlally essential, I have deemed tbt tt he exclusion of the hundred pages or so which this omission permits, amply compensates for the few seconds of additional labor which the lack of them may occasionally involve. Qeaking for myself, as regards Railroad work, I must say that for one time that I work by logarithms I. work a hundred times by naturals and I know that most engineers would bear similar testimony. In the Astronomical problems in the latter part of the book, considerable labor may, of course, be saved by the use of 4 CONTENTS . RAILROAD LOCATION . GENERAL CONSIDERATIONS . SEC . 1 . C onditions of Economical Location ............................... P . AGE 1 2 . TrainResistances ................................................. 2 3 . RollingResistance ........................................... 2 4 . Resistance due to Oscillation and Concussion . .............. 3 5 . Atmospheric Resistance .................................... 3 6 . Resistance due to Curvature ................................ 4 7 . Resistance due to Gravity ................................... 4 8 . Diagram of Resistance ........................................... 5 Limiting Velocity on any Grade . ........................... 8 9 . Propelling Force of Locomotive ............................... 8 Coefficient of Adhesion ..................................... 8 Sliding Friction .............................................. 8 Limiting 1. H. P . .............................................. 9 Weight on Driving. wheels ................................... 9 Grate-surface ................................................ 9 10 . Dlagram of Propelling Force .................................... 10 Limiting Speed for any given 1. H. P . ........................ 10 Internal Frictional Resistances ................................... 11 Back. pressure, Wire-drawing, etc . ........................... 11 11 . Diameters of Driving-wheels ................................ 11 12 . I. H. P. required at any given speed .............................. 12 Most Economical Speed .......................................... l 2 Limiting Grade ................................................... 13 13 . Weight of Locomotives and Rolling. stock ........................ 13 14 ... --This text refers to the Paperback edition.