Comparison of dog spikes and screw spikes – two typical railroad spikes

A railroad spike, which is equipped with an offset head, is a large rail nail used to secure and fasten the rails in the railway system. With the development of industrialization, the rail spike was invented by Robert Livingston Stevens and the first use was in 1832. The main function of railroad spike is to ensure the correct position of the gauge. And the common sizes are usually between 9-10/16 inch and 5.5-6 inch long. With a flat edged point and chisel-shaped, the spike can give greater resistance to loosening. During the transportation of railway, it is not necessary to require the spike to provide a strong vertical force, which provide a nice environment than can allow the rail track freedom of movement.

In the past several years ago, the installation of railway is mainly by manual work. To spikes, it were driven into wood sleepers through a heavy hammer by hand. Later, in the times of industrialization, the machines appeared and replaced this manual work. Through adding steel bands on the wood or pre-boring spike holes, the split of the wood can be limited. Through the analysis of railway fishplate market in North America, North America has a great demand of railway materials. There are many various international standards such as AREMA, ASTM, UIC, GB, BS standards for different kinds of railway tracks. As to the total sales of exports by the end of 2014, it reached $251,334,709 and the growth rate is 15.5% in the same time. For United States, ASTM A65 standard is a common standard used for different carbon steel contents.
Among the railroad spikes, dog spike and screw spike are the two common railroad spikes in the market. 

When first introduced in 1860 in France, then the screw spike shortly became the common railway material in continental Europe. The screw spike, also called rail screw, is a large screw used to fasten any two railway tracks. Besides, it is also used to fix tie plates or fix into a hole bored in the sleeper. Owing to the greater fixing power and the feature that can be combined with spring washers, the cost of manufacture of the screw spike is higher than the rail spike. In the common life, the railroad screw spikes are mainly used in some heavy rail applications as well as in some peat works, garden festivals, leisure parks and so on.

At before, the screw spikes are usually used to fasten the ribbed base plates and sole plates to wood sleepers. With the construction and development of the concrete sleepers, the screw spikes play an important role in railway fastening systems with the help of a plastic dowel. In order to meet the different use and standards of railway tracks, the screw spikes can be classified into so many types. Now all railroad spikes are made out of carbon steels. Through the different specific geographic requirements such as lengths, diameters, drive heads and thread profiles, the railway screw spikes can be classified into four types: Ss series sleeper screw, square head screw spike, hexagon screw spike and double-head screw spike.
Ss series sleeper screws

Square head screw spike
 

 

Why dog spike is so called?
Dog spike is another important component of railroad spikes. Because of the two lugs on either side, the dog spike looks just like the dog’s head. Just like the screw spikes, the dog spikes have the similar dimensions. But as to the head, it has a pointed penetrating head. 

Among dog spikes, the dog screw is a special one. Invented by AJAX fasteners, the dog spike is usually a rail screw with a shallow double pitch thread. In order to fix rails straight to the rail sleepers, it is necessary to have a flange with a radius. During insertion, with the help of the patented “wave” thread form and better pull-out resistance, the dog screws can reduce damages to railway sleepers. In a way, the dog screws can replace the dog spikes when they are firstly designed and invented. So the dog screws shouldn’t be put in an old dog spike hole. 

Comparison of dog spikes and screw spikes

Surface

The screw spikes are the railroad spikes with the screw thread on the surface. But as to the dog spikes, it has a pointed penetrating head with a smooth suface.

 Power

As to the holding power, the screw spikes can provide more than twice of the power than the dog spikes.

Cost

Because of the greater fixing power and the feature that can be combined with spring washers, the cost of manufacture of the screw spike is higher than the dog spikes or dog nails.
In a word, the railroad spikes are all used to ensure the safety of the railway fastening system and railway transportation. So if the railroad spikes are used in the right place, it  will have a striking effect, no matter what type it is.