"A large nail or pin, generally of iron. The larger forms of spikes, particularly railroad spikes, are chisel-pointed, and have a head or fang projecting to one side to bite the rail. Spikes are also made split, barbed, grooved, and of other shapes." —Whitney, 1889
<p>Illustration of two forked spikes. When driven into wood, the points spread and hook into the wood.

Forked Spikes

"A large nail or pin, generally of iron. The larger forms of spikes, particularly railroad spikes, are…