18 



Appendix A. 

 THE ''POST" TIE. 



This tie, of which so much has been heard, is probably the most suc- 

 cessful of all the various types of metal ties that have been put in serv- 

 ice, and the success is largely due to the care which has been taken in 

 notiug- the results obtained and in making such imx)rovements as expe- 

 rience has shown to be desirable. Consequently, the present form of the 

 tie is the result of many improvements, and represents several years of 

 experience and careful study. It is a cross-tie rolled from mild steel 

 (Bessemer, Thomas, or Siemens-Martin )5 its section is that of an inverted 

 trough, with flaring sides forming a section of a polygon j it is narrow 

 and deep in the middle, the ends are closed, and the bottom edges are 

 thickened to form a rib. One of its special features is its varying thick- 

 ness, giving an ample tliickness of metal at the rail seat, where the 

 greatest strength is required, and a less thickness at the middle and 

 ends. Thus the weight of the ties as now used is from 110 pounds to 

 121 pounds each, corresponding to 12G.5 and 139.15 pounds if they were 

 of uniform section. This feature represents, therefore, an economy of 15 

 per cent, of metal as compared with a tic with a uniform thickness equal 

 to the maximum thickness of the " Post '' tie. In the operation of roll- 

 ing, the varying thickness is given and also the shape of the tie, while 

 the bending of the ends to give the rails an inward inclination of 1 in 20 

 (in accordance with European practice) is done during the same opera- 

 tion. 



The shaiDe of the middle portion of the tie is designed with a purpose, 

 as ifc is claimed that by narrowing this portion the ballast is kept from 

 working away from under the rail seat, and in this way a stable road-bed 

 and track are secured, thus diminishing the work of maintenance. It 

 prevents the tendency of the ballast to work towards the middle and 

 form a ridge on which the tie would rest, giving a rocking motion to the 

 track, but gives it a tendency to pack well under the rail seat. The in- 

 creased depth of this portion gives additional strength to resist bending 

 and also offers increased resistance to creeping. 



The following are the principal dimensions, given in the original 

 metric measure and also reduced to feet and inches: Length over all, 

 2.55 to 2.G5 metres (8.301 to 8.092 feet) ; width over all at rail seat, 235 

 millimetres (9.40 inches); width over all at middle, about 5.30 inches; 

 width of rail seat, 110 millimetres (1.40 inches) ; width of end, 280 milli- 

 metres (11.20 inches); depth under rail, 74.5 to 75.5 millimetres (2.98 to 

 3.02 inches) ; depth at middle, 125 millimetres (5 inches). Thickness of 

 cross-section at rail seat varies as follows : Thickness at bottom of flange, G 

 millimetres (.24 inch) ; thickness at upper part of ilange, 7 millimetres (.28 

 inch) ; thickness at rail seat, 9 to 10 millimetres (.30 to .40 inch) ; thick- 

 ness at bolt-holes, 12 to i;» millimetres (.48 to .52 inch) ; thickness at 



