From this may be calculated at a rate of interest of 4 percent, for a 
wooden tie lasting ten years, N^l.OX,,, and compared with a creosoted 
wooden tie lasting twenty years, N^ssLSET,, j that is to say, if the metal 
tie lasts tw ice as long as our best oak ties, its original cost may be al- 
lowed to be Dearly twice as much as the oak tie. It' it lasts twice as long 
as a creosoted tie of twenty years' duration, it may cost one and one- 
half as much as this to be only equally as expensive; if duration and 
cost of renewal alone are considered, or, as our best oak ties do not aver- 
age more than eight years' life, and a metal tie can be safely said to last 
three times that period, reckoning rate of interest at 5 per cent., at 
present juices for metal, and considering cost of renewal, it would be 
economy to use metal ties when oak ties cost 70 to 80 cents, and pine 
ties lasting five years cost 50 to 55 cents. 
ADDENDA— JOINTED AND COMPOUND CROSS-TIES. 
As the object of these notes is to point out where a saving in the use 
of wooden material for railroad construction may be effected, the fol- 
low ing suggestion may find proper place here, describing a system of 
using up old wooden ties practiced on the Netherlands State liailways. 
' The best wooden ties fail at the point where the rail rests on the tie, 
while a length of from 3 to 3Jfeet between the rails remains quite solid. 
Laving two such lengths sawed offend to end, they are joined together 
by a length of inverted chaunel iron let into the timber, so that its web 
lies upon the upper surface. The rail rests on the channel iron, which 
thus prevents it from wearing into the tie. (By bending, the l-in-20 
cant, if required, can be given.) 
The saw ing, dressing, boring, and putting together of thesecompound 
wooden and iron ties can be done in wet weather by the trackmen, thus 
saving in the cost. The laying and batting up are the same as with 
ordinary ties. 
As these compound ties have four end-faces, they offer increased re- 
sistance to lateral motion. 
In duly, 1882,a quantity of these ties were laid in a main linethrough 
a station, and in September of the same year, a further number on a 
main line curve of 50 chains radius and a gradient of 1 in G2, over 
which ran thirty trains a day, some of them expresses. Both of these 
lengths have required nodifferent treatment from the adjoining lengths 
laid with ordinary wood ties, while the gauge has remained exactly true. 
In a similar manner may be joined together short metal waste pieces 
which are left in making steel ties, in order to reduce the price of the 
perfect steel tic 4 , the waste pieces being riveted together. This attempt 
to produce a cheap steel tit 1 , at ieast for secondary lines, may be con- 
sidered quite successful. 
The Netherlands State Railway in June, 1885, laid a number of such 
ties on a curve of 20 chains radius with a gradient of 1 in 62. These 
