Litchfield enquirer., 1879-02-06
WHOLE NO. 2748

rather indicate that 1t has at some time been overstrained and become unfit for such service Fatigue of mentals' is the name which has been applied to the effect produced on iron and other metals by repeated heavy strains and it has also been compared to the condition of the muscles of the animal frame when strained beyond their reasonable powers of endurance They may for time endure the load and probably few repetitons of it. but the result generally is the total suspension of thos. qualities by which their elasticity and powers of restoration are maintained"
 ''It was formerly believed that iron, 1t not strained beyond its elastic llnit, was practical ly indestructible, but recent investigations and experiments show that repeated stralns even within this limit, may ultimately produce rupture the time of such rupture depending on the severity and frequency of such strains"
 In confirmation of this view paper hy Prof 4ssor Thurston of the Stevens Institute of Technology, is appealed 10 ny the Repol
 he conclusion arrived at IS this-tnat rods must he made so large that no str in which is likely to cone upon them can ever exceed their limit of elasticity. It is never possible to determine dccurdtety the amount of strain that can be resisted {: i1rst, because the iron itself is seldOm uniform IF strength; sgc- Ond because the tension is unequal on the rods they are not all strained alike, and Il loose nut may increase a strain of ten tons to the square inch to fifteen tons, or even thirty if the whole pressure comes upon single rod: third because of the uncertain force oi sudden shocks and vibrations as of the su lden com ing of ffty.tOn locomotive upon the bridge; fourth, the loss, by iron, not of it's tensile strength, but of it's power 10 sustain sudden shocks, by the effect of extreme cold. CThe week preceding the disaster at Tarihville was a very cold one--15o, 1So, and l97 below zero The danger is that the fracture will he at the screw thread the weakest part of the rod--where it is effectually concealed from sight. The commissioners have been carefully examining all the wooden railroad bridges in Connecticut on this very point of danger from insufficient suspension rods; and they hnd that causes of danger are Cor have been, until d few months ago. present in many hrldEes ;-
 Assuming rolling load of 1 9 tons per lineal foot, being about the weight of train of heavy locomotives, we have found that very many of the wooden bridges in the state, in common with the one at TarifviIle, have been built with maximum strains on their rods varying from ten to fifteen tons per square inch, instead of five tons, as recommended by the best engineering authorities. The conpc- tiiOn among contractors and bridge builders, and their desire to underbid each other ou the one hand, and the want of care among rail road mana er3 not requiri g andards f absolute safety on the other. are among tue
 
 The special point of danger is al the screw threads, where the thickness of tine rods is re- duced about one third' by the cutting of the thread at top and bottom, to receive the nuts. A sectional area of three of these Tarifviile rods s' owed an actual difference of 45 and 4I per Cent in the size of the rod. as compared with tue parts where the thread was cut. The dangerous strain on this hidden part of the rod would remain unnOticed- the main part of the rod appearing all right till the crash comes. Here is the remedy:
 We therefoe consider the use of such rods in bridge work highly objectionable A few If the oldest roads in the state, learning wis do Il by long experience, have in their wooden bridges, recently constructed, used rods with anlar sei or upset ends having diameter at bottom of thread as large or larger than ihe
 main part 0t the rod. Builders of the best iron bridges have recognized the importance of such rods in the general use of them in their work. Their universal use on wooden bridges would be a safeguard against accidents, since if over strained u e. are likely tO elongate SuiiiCi ntly to attract atttuuOn. instead Of shapphs OH suddenly at the base of the nut without previ- ous warning"
 An additional improvement would be the use of the United States Standard or Frankliu Institute screw-thread, in which the sharp an s,es at top and bottom of thread are taken ot. The principal lpssOn therefore, taught ny the Tarifville tlister is the necessity of larger suspension rods than those heretofore used in
 most of the wooden railroad bridges of the state If in that bridge the broken rods hal been one quarter inch larger in diameter, with lpset ends, their area and efficiency would nave been nearly doubled. their liability tO 1rcakaye accordingly dininished, and their strength near the standard recommended by the best engineers.
 We cannot evel yet leave this particular subject The commissioners deserve credit for prompt action in senlinr out circular. last winter, to every railway company in the state calling attention to the insufficient char acter of the rods on all the How truss bridges, md pointing out, in detailed statement of the case. the particular nature of danger. Be ing without power to compel tue substitution of larger rOds the board could only direct the attention of railway managers to the danger; and the result has been a prompt and general strengthening of the bridges If (Hs would appear) there are still two 0r three instances where this has not yet been done, the atJeui n of the manager should he directed to the sul- ject in way to produce results. The safrty Df life and limb IS the first consideration.
 Concerning the annual returns made by th" different companies the new fOrM is reported to work satisfactorily, but in few instances the returns are nj ,hly unsatisfactory owing to tht incorrect way in which the books are kept. \ committee of five (Mr Woodruff represent ing ConnecticuDwas appointed at the congen- tiOa, last November, of railroad commission ers held at C0lu nbus, Ohio, to correct such evils as this, by arranging, if possible, uni form method of book keeping, and in the forms of returns. Each state now has ifs own form. If the com .nittee succeeds, there will be uniformity. - .....
 l..-.er THE EARNINGS. ..
 The gross earnings of the year have .reen S1O 806 494 IS, a falling Of o6 sS5J4 793 92, or 2 72 per cent; this is little Improvement on last year, when the falling off vas D S6 per cent The passenger earnings were S50J2, 299 GA. against Ss5, 157 99s. 10 last year, loss If $95. .607. 46. or ,89 per cent, and from freight, $4. I'll. l09. 15, against $5,006. 332 5l last year, loss of $235 723 45, or 4 94 per cent Last year the passenser earnings slow ed failing off or nearly 12Jer cent from the previous year, and there was a gain of ] t6 per cent. in freight earnings
 The gross expenses have been s1 GS0 4GN G1 or SIS per cent. of the gross eaYaiHgs ab,u' tae same last year, when the eXl e ses were 62 per cent. of the gross earnings.
 The total net earnings were S4 12f 093 5l, being $S0, 494 go less than last year.
 Seven companies paid S2, 5iD. 1S0 in divi- dends, OH $27, 597, 800 of stock issued. being at the rate of 9 39 per cent. The seventeen com panies made no dividends.
 The gross earnings per mile averaged s. 295. 79-the Hartford and New York road ;S27, 93l .42 and the Shepaug $l.476 03, The gross expenses averaged $5, 12S B p"r nlle-- being $l4. 327G9 on the Hartfprd ana New York, and l.169 00 on. the Shepaug, Tine net earnings averaged $3s i67 4j per mile h"ing $l3, sos "A on the Hartford and New York. and $136 90 On tn, New Canaan
 It is evident that the companies, this Inst year, have been doing mere work for less nl1n- ey. The Wa le nnnher of passenger carried was 9,695, 782. and increase of 6 09i. with mileage of 2i3 472 6S1; an increase Of I'll .9O2 miles. The freight carried was s. 791 195 tons; an increase of 1G1, 52U tons with neile- age of 154, 852, i2l all increase of I1,7l9,01+ miles. ".''
 sgp.. .es.. a..i .t..rE ot.H..#
 THE ACCIDENTS, FOR THE YEAR.