Replacement parts for some of the older machinery are no longer available from the original manufacturers. Workers have turned to third-party websites, retired equipment and parts fabricated in-house to keep some systems running.
The inspector general said older equipment also lacks modern safety features designed to protect workers.
The Metropolitan Transportation Authority’s 2025-2029 capital program includes major improvements at more than 70 substations, including 21 full replacements, according to the report.
The agency is also developing a centralized system for tracking equipment defects, repairs and maintenance.
The audit made seven recommendations covering maintenance tracking, equipment records, defect monitoring, protective equipment and post-incident investigations.