Quadruplication n. : The act of making fourfold; a taking four times the simple sum or amount.

Example:


Taxonomy
double track, tunnel, single track, trains, duplication, railway, two tracks, bridges, loops, bridges and tunnels, track line, signals, high speed trains, one track, accident, hand running, provision, control trains.

Defination from the web:
Quadruplication) Jump to: navigation, search ... A BNSF Railway intermodal train passes some maintenance of way equipment on the double track mainline in Prairie du Chien, Wisconsin. ...