CHAPTER VII 
live and dead loads, wind pressure. 
By making inquiries of a number of railway officials tlic author lias ascertained 
” uit the heaviest engine used in Japan weighs about thirty- three English tons. It 
ls a t an k engine about twenty-eight feefc long and rests upon three pairs of wheels, 
^vliich sii|)port (,] ie weight nearly equally, and whose axles are very nearly tlie same 
distance apart. 
It is the opinion of all the officials consulted that this is about as heavy an 
® 1J gine as will ever be put upon tlie present Japanese roads, or upon any future roads 
uilt according to the same general design. 
〇 11 this account the author lias assumed the engine specified in the begiiming of 
把 last chapter as a standard for proportioning bridges? Its weight is thirty seven 
，】:<l a halt American tons or about thirty three and a half English tons, bo it is a 
11 e heavier than any engine in uso in Japan. Such an engine carries its own coal 
and water, so is not followod by a tender. Tlie engines with tenders are so much 
l ° 1 ei 山⑽ tlie tank engines that the combined weights of the former exceed that c f 
le by only two or tliree tons, and arc distributed over forty-two feet instead 
^venty-eight, so that it is unnecessary to consider tlio effect upon bridges of the 
combined eugine and temler loads. 
It is uuusnal in this country, altliongk quite common in America to couple two 
n 0111 es at the hetul of n train, nevertheless such an nriangemont ilocs occur here 
°ccasionally > so it lias been adopted in this treatise ; because bridges slioukl be 
1 1 opoi tioned for tho greatest loads that can ever come upon them. 
Iu regard to car loads the iu formation obtained shows that the freight cars 
W ien 1 〇 11 如 (1 briiig the greatest loads upon the track, and that a loiulecl car weighs 
110 laoie ^ ian eight tons twelve liuiulred weight or 19,204 pounds. The length of 
^ dl f lom Sutler to buffer is eighteen feet, making the greatest loatl per linoal foot 
1 〇 7 〇 pounds. 
Now as cars arc sometimes overloaded, although it is very bail for the springs 
against the rules of tlio railroad, the author lias thought it best to assume a car 
a( of 1 200 pouiuls per lineal foot for spans under one liuutlred aiul fifty feet in 
en otli, aiul to reduce it gradually to 1050 pounds for spans of three hundred feet. 
乃 16 reasou ' v 】、y öueh a re luction is permissible is because the chance of a long 
‘ pan e'ei. being covered from end to end by tlie maximum loatl is very small, while 
