CROSS TIES 297 



Hatt at Purdue University to compare the force required to pull nail and 

 screw spikes show some very interesting results. The common nail 

 spikes were 5! in. long and ^ in. square in cross section and weighed 

 165 to the 100 Ib. The screw spikes were also 5^ in. long, with a diameter 

 of f in. at the root of the thread and weighed 85 to the 100 Ib. The 

 result of these tests showed that the resistance of the screw spike was 

 3.15 times that^of the nail spike in chestnut, 2.1 times in loblolly pine and 

 1.8 times in white oak. Other tests showed that the screw spike is far 

 superior to the nail spike in resisting lateral displacement. The loosen- 

 ing of the ordinary spike permits of the accumulation of moisture around 

 it and furthers the rotting of the tie. When respiking is practiced the 

 holes are sometimes filled with treated hardwood tie plugs. 



The dilatory introduction of the screw spike is due chiefly to the abun- 

 dant and relatively cheap tie timber available for our railroads. With 

 the increased cost of cross ties and use of treated material, length of 

 service is of great importance and this can be greatly enhanced by the 

 use of devices to prevent abrasion and mechanical failure as well as by 

 preservative treatment. Aside from this consideration, the objections 

 raised to the use of screw spikes are 



1. Increased initial cost over nail spikes. 



2. It requires a longer time to insert screw spikes and this is likely 

 to delay traffic at times. 



3. Screw spikes require special machinery to drive them and 

 boring both of which require larger labor and equipment costs. 



4. Difficulty of re-gauging the track from time to time as track 

 becomes worn. 



In justice to these spikes, however, it should be mentioned that 

 these objections are largely of minor consequence. 



2. Tie Plates. These are placed immediately between the tie and the 

 rail and are designed to distribute the impact and weight of the passing 

 trains over a greater area than that afforded by the base of the rail and 

 thus reduce the likelihood of rail cutting. With the use of increased rail 

 weights, such as 100 and 1 10 Ib. and even heavier rails with their wider 

 flanges, the tendency to rail cutting has somewhat diminished. But the 

 increasing weight and frequency of trains has more than counterbalanced 

 this advantage on most of our larger railway systems. 



Many forms of tie plates have been introduced and used. Wooden 

 tie plates have been tried, but without much success, because they soon 

 split and buckle under the great impact. In order to be effective tie 



