noun
track maintenance
Refers to the inspection, repair, and upkeep of railway tracks and related infrastructure. Often used in compound terms like 保線作業 (track maintenance work) or 保線区 (track maintenance section).
夜間の保線作業で電車が運休になった。
Trains were suspended due to nighttime track maintenance work.
彼は鉄道会社の保線区で働いている。
He works in the track maintenance section of the railway company.