Repurposed fastening tools from the pre-War railway system, these spikes are capable of crippling and delimbing those unlucky enough to be the target of their fire. Their speed and kinetic energy are well into the lethal range, and their velocity has been fine-tuned to maximize effectiveness.
The railway rifle is currently the only weapon in Fallout 4 to use this type of ammunition.
The utility protectron has nail guns integrated inside one or both of its hands. In combat it uses those nail guns as weapons and fires railway spikes. Upon death, it will often have variable amounts of railway spikes on its remains.