single-track

[ sing-guh l-trak ]
/ ˈsɪŋ gəlˈtræk /

adjective

(of a railroad or section of a railroad's route) having but one set of tracks, so that trains going in opposite directions must be scheduled to meet only at points where there are sidings.
having a narrow scope; one-track: He has a single-track mind.

Origin of single-track

An Americanism dating back to 1825–35
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for singletrack (1 of 2)

singletrack

/ (ˈsɪŋɡəlˌtræk) /

noun

an off-road trail used by cyclists, wide enough for only one bicycle at a time

British Dictionary definitions for singletrack (2 of 2)

single-track

adjective

(of a railway) having only a single pair of lines, so that trains can travel in only one direction at a time
(of a road) only wide enough for one vehicle
able to think about only one thing; one-track

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012