overhaul

Compared meaning: to thoroughly update or repair equipment or systems (verb).

比较义项：对设备、系统等进行全面更新或彻底检修（动词）。

• modernize

  Emphasizes bringing something up to date by adopting modern technology, equipment or methods; does not necessarily imply fixing something broken.

  强调通过采用现代化的技术、设备或方法使某物跟上时代；不一定意味着修理坏掉的东西。

  The city plans to modernize its transport system with digital payment methods.

  这座城市计划用数字支付方式使其交通系统现代化。

• overhaul 本词

  Emphasizes a thorough examination and repair of something worn or faulty; does not necessarily mean making it more modern or up-to-date.

  强调对磨损或出故障的东西进行全面检查和修理；不一定意味着使其更现代化。

  Mechanics overhauled the old engine to fix years of wear and tear.

  技师们彻底检修了这台旧发动机，修复了多年磨损造成的问题。

Modernize and overhaul both mean making large changes to equipment, but focus differs. Modernize stresses bringing something up to date with modern technology, not necessarily fixing something broken. Overhaul stresses thoroughly checking and repairing something worn or faulty, not necessarily making it more modern.

两词都指对设备或系统进行大规模改动，但侧重点不同：modernize 强调引入现代化的技术或方法，使其跟上时代；overhaul 强调全面检查并修理，重点是解决问题或磨损，不一定涉及“现代化”。这里只比较各自给出的这一义项，不涉及其他用法。