Although there are many different types of buffer stops, they can be primarily separated into two types, fixed or friction.
Fixed buffer stops are a type of permanently fixed railway buffer that won't move or absorb energy when a train makes contact with it. The most common type of fixed buffer stop has a framework built from sections of shaped rail and a contact plate placed at the same height as a train's buffers to serve as the initial point of contact. Other types include wooden framed buffer stops constructed to a similar shape, concrete blocks and wooden boxes filled with sand or coal.
Fixed buffer stops have been used almost since the dawn of the railways. They are a crude and primitive solution to stopping trains running off the ends of sidings or crashing into terminus platforms. Because they do not absorb kinetic energy, heavy damage can be sustained to rolling stock that comes into contact with them. As a result, friction buffer stops that can absorb limited amounts of energy from a slow-speed impact started to emerge towards the end of the steam era and are now commonplace at most terminus stations.
Despite their flaws, a large number of fixed buffer stops are still in use today but are more commonly found in low-risk locations such as sidings. A few are still used at stations but are likely to be proceeded by a sand-trap or other device for slowing a train before contact is made.