Expanding a rail line to four parallel tracks is a major infrastructure upgrade used to drastically increase route capacity. In a quadruple-track arrangement, slower local or freight trains are physically separated from high-speed express or passenger traffic. This eliminates bottlenecks caused by trains running at different speeds over the same rails, though it requires a massive footprint and complex switching.
We're going to quadruple the corridor between the junction and the yard to keep the commuter trains out of the way of the manifests.
Most quadruple track separates traffic by direction (two northbound, two southbound) or by speed (express tracks in the center, local tracks on the outside).
Also heard as
- four-track
Related terms
Double track
A railway line built with two parallel sets of tracks to allow simultaneous traffic in opposite directions.
Main line
The principal track or tracks of a railroad between terminals, where trains need authority to run.
Multitrack
Describing a railway line or corridor equipped with two or more parallel tracks.