Railroad siding:
An auxiliary track adjacent and connected to the mainline that allows a train to move, stop, or pass another train without being on the mainline.
Railroad bridge:
A structure for carrying one or more railroad tracks aerially over a depression or obstruction such as water, a roadway, or another railroad.
Third track:
Provides for trains what a third highway lane provides for vehicles; the third track allows a faster moving train to pass a slower moving train without obstructing train movements in the opposite direction.
Road bridge:
A structure for carrying passenger vehicles aerially over a depression or obstruction such as water, highway, or railroad.
Clearance:
The limiting dimensions (including height and width) for railroad equipment or shipments that allow trains to operate clear of obstructions along the right-ofway such as bridges, tunnels, platforms, or structures.
