A double junction is a railway junction where a double-track railway splits into two double track lines. Often, one line is the main line and carries traffic through the junction at normal speed, while the other track is a branch line that carries traffic through the junction at reduced speed.
A number of configurations are possible.
Because double junctions contain a merging conflict as well as a crossing conflict, there is risk of a collision if train runs a red signal. This risk can be partially mitigated by never having both switches point towards the crossing at the same time, but collisions are still possible.
Single lead junctions are higher risk than other types due to the possibility of two trains colliding head-on on the branching line.
Grade separated junctions contain fewer conflicts, and are thus lower risk than other types.
Systems independent of the junction design can also be implemented, such as ATP and Train stop.