119 
carves as well as on the straight road, and to permit the elimination of 
unavoidable faults occurring in fabrication. 
(1) To allow shiming up, wheie t lie action of frost makes it neces- 
sary. 
The forces which work upon the fastenings are: 
(1) The horizontal forces tending to press the rail-foot OutwaTd. 
(2) The vertical forces tending to raise the inner edge of the rail-foot. 
To counteract these forces, it is nec< ssaiy, with bolt fastenings, to pro- 
tect the bolt in its entire length against side forces tending- to bend it 
or wear it away. To effect this the bolt must be placed as near the 
rail foot as possible, so as to reduce the leverage of the vertical force as 
much as possible. Small number of parts and a simple form is most de- 
sirable. 
The nature and good service of the fastenings has also great bearing 
upon the cost of keeping the road in order. 
LIFE. 
The life of iron ties has been variously estimated by those in favor 
of the system at from thirty to fifty years ; opponents place it at not 
more than twenty years, that of the best wood ties. This last esti- 
mate is, however, disproved by the more than twenty years' experience 
with longitudinal ties on the Brunswick railways. These were laid in 
1864, and in 1882, on thorough inspection, were found but slightly 
affected by rust. 
In fact, iron ties suffer less from atmospheric influences than wooden 
ones. 
Ties on the Bergisch-Markisch lines, after being laid for eight years 
in a badly-drained ballast, were found to be not more affected by rust 
than the rails. 
Mr. Kalff, at the convention in Brussels, stated that metal sleepers 
laid down twenty years ago were fouud in perfect condition. Only, for 
ties kept in reserve by the side of the line or in damp tunnels and 
similar localities, or if transported over the sea, a coat of tar or paint 
might be fouud advisable. 
With the better form and heavier sections now used, the breaking of 
a tie is so unusual as not sensibly to affect the annual charge. 
Whatever the cause, steel rails and ties undoubtedly rust much faster 
than those made of iron. 
Mr. P. II. Dudley, 0. E., an expert on railroad matters, says : " So 
far as atmospheric agencies are concerned, the German experience 
would be a good guide here. The oxidation of rails at least shows in 
most localities no greater rapidity than in Germany. Failure in this 
country of metal ties, as far as I have seen them used, was due to the:r 
form not meeting the conditions required of a metal tie." 
