Not to be confused with a Train-replacement bus service

A railbus is a very lightweight type passenger rail vehicle (typically non-articulated or rigid frame) that shares many aspects of its construction with a bus, usually having a bus, or modified bus, body and having four wheels on a fixed base, instead of on bogies. These railbuses, a design developed in the 1930s, have evolved into larger dimensions, performance and characteristics similar in appearance to a light railcar, and today the terms railcar and railbus are often used interchangeably.