Railguns, also known as rail guns or rail cannons, are large weapons, using electromagnets to fire slugs at high velocity. There were multiple projects attempting to create successful designs before the Great War.
The X277 "Viper" magnetic rail cannon was developed for the U.S. Military by West-Tek. The weapon uses energy cells to propel a depleted uranium round across a series of magnets discharging it at extremely high velocity. Deemed too costly to produce on a mass scale, the project was abandoned in 2044. The only known prototype was displayed in the Museum of Technology in 2077, but is no longer present as of 2277.