The gun uses railway spikes as crude flechettes. Though only moderately damaging, it is very effective at dealing limb damage (due to a 3x limb damage multiplier), able to cripple limbs with just one shot. On the killing shot, a spike may tear off the struck limb or head, and possibly pin it to a fixed object, for example a wall or the floor. With each shot, the Railway Rifle makes a distinctive "toot-toot" noise similar to a trains whistle.
While it has a low amount of spread, its accuracy is not perfect and the rifle will often miss at long range. However, its projectiles have much more mass than bullets, making it more effective at short to medium ranges, and most effective in V.A.T.S. where its limb-destroying effects can be put to precision use. It is also remarkably effective at disarming enemies, as it will often launch their weapons a substantial distance on a V.A.T.S. hit. It has a high critical multiplier stat that, depending on your base critical chance, may make the railway rifle one of the best non-unique Small Guns.
The railway rifle can fire a total of about 224 spikes, the equivalent of 28 reloads, from full condition before breaking.
Laszlo Radford uses the railway rifle, he is a random encounter who may be found at certain "random encounter" locations throughout the Wasteland, but only after you have obtained at least 1 schematic of it.
All of the components can be found in Fort Independence. Simply walk into the building and go straight and open the door. On the back left shelf, all the way to the left is a crutch. After that, back up and go right. There will be a staircase, then a door afterwards, open the door and proceed downward. Go into the cubicle on the far end of the room on the right.There will be shelves containg 3 fission batteries, and a steam gauge assembly move into the other room on the same floor. Turn right, and there will be a table with 2 pressure cookers
Seagrave Holmes' computer terminal in Rivet City contains an entry about his failure to create a weapon that fires railway spikes. The entry describes his attempts at using rubber bands as a propulsion system (similar to the surgical tubing on the dart gun), and possibility of making his contraption steam-powered, hinting that he is, possibly, the original inventor of the railway rifle.
The stock of the railway rifle seems to be an actual weapon stock, similar to that of a combat shotgun, instead of appearing as a crutch like the schematics intended. The hand grip of the crutch can still be clearly seen under the barrel section attached to the piston.
Curiously, railway spikes do not create ripples when fired into water.
Oddly, all of the components for the railway rifle add up to a total weight of 27 pounds even though the weapon's weight is only 9 pounds.
The pressure gauge by the barrel of the railway rifle will indicate high pressure until it is fired once, then low pressure until it is reloaded.
Fallout: New Vegas includes a brief cameo of the railway rifle, seen on the far wall of the "hidden" weapons room in Mick & Ralph's. This version of the weapon is a non-interactive static mesh (i.e. a decoration) rather than a working weapon. Most of the other resources for this weapon remain in the game's files, but no actual, working version of the weapon exists within the game itself.