What are the connections in the railway system

Common joint:
It is the most basic kind of joint, which is connected by two fixed length rail with splints and other parts into a continuous rail line, and a rail gap of 8~10mm is set between the two rail ends for the rail to expand and shrink.
Due to the existence of rail cracks, vehicles will have periodic impact when passing through the joint area, which may cause the damage of rail and ballast, such as rail end collapse, stripping, saddle wear, and ballast sinking, collapse and buckling. Therefore, on busy arterial lines, common joints have been replaced by welded joints.
Shaped joint:
Used to connect two rails of different section heights.
It is also used at the junction of different types of tracks (such as the connection between the main line and the station and yard line, usually the terminal of the station and yard access section).
Electrical connection:
For automatic block and electrification area, power supply circuit.
When the rail is used as the traction current circuit of the subway line, the steel strand is welded to the outer sleeve of the rail joint; When the rail doubles as the transmission channel of the signal track circuit, both ends of the track connection wire (guide wire) can be driven into the guide wire hole on the waist of the rail near the end of the rail.
Insulated joint:
It is used for automatically blocking the rail joints at both ends of the partition to cut off the current and prevent leakage.
The insulation joint is separated by nylon rail head piece, nylon splint and nylon bolt sleeve to prevent the current from passing through and play an insulating role.
Insulated rail joints are also used to separate track circuits for signaling systems.
Freezing joint:
Used to prevent rail expansion.
The frozen joint is a rail joint with high-strength bolts, the joint splint and rail clamp, the rail bolt hole is inserted into the crescent gasket, relying on the friction between the joint splint and rail and the support force of the bolt, forcing the two rail ends to stick closely, so that the rail joint no longer changes.
Adhesive joint:
The high strength adhesive is applied to the rail end and the contact surface between the splint and the rail, and the rail and the splint are glued together as a whole, and can play an insulating role.
The insulation properties of cemented rail joints are improved, and the stress state is also improved.
Expansion joint:
Also known as temperature regulator, it is used for tracks with large rail end expansion, such as tracks on Bridges with spans of more than 100m and seamless line expansion areas on Bridges.
Straight through joint:
The structure is similar to the ends of two pipes connected to each other, and two steel rails can be directly connected.
The advantage is that the structure is simple, easy to install, the disadvantage is that the connection is easy to wear, and the life is relatively short.
Socket joint:
The structure is similar to the straight-through joint, but the socket joint has a plug-in structure at the joint, which can better prevent wear.
The advantage is that the connection is stable and the life is relatively long, but the installation is relatively complex.
Shear joint:
The two rails are cut at a certain Angle at the joint, and then the two rails are joined together by a certain structure.
The advantage is that the connection is stable and the life is long, but the installation is more complicated and requires professional technicians to install.
Expansion joint:
An expandable structure is provided at the joint, which can be automatically adjusted to keep the connection stable when the railway expands due to temperature changes.
The advantage is that the connection is stable and the life is long, but the installation is more complicated and requires professional technicians to install.