WASHINGTON, DC — Metro is in the middle of a complete mess of an overhaul due to safety and maintenance problems with their tracks, and now an alarming new report indicates that the much-ballyhooed new trains WMATA purchased may be damaging the tracks further.

WAMU reports that federal track inspectors who examined tracks on the Green Line between the Georgia Avenue Northwest and Petworth stations found damage to fasteners. The discovery was made after residents near the tracks complained that their homes were vibrating. Inspectors determined that using the new 7000-series rail car trains, which are much heavier than older rail cars, could be contributing to the problem, according to the report.

WMATA decided to purchase 528 7000-series rail cars from Kawasaki in April 2013. The trains are intended to replace the 1000 and 4000-series cars. The first of these trains debuted on the Blue Line in April 2015. This isn't the first time concerns have been raised about the 7000-series in recent months. WTOP reported in January that the trains were going 5,000 to 10,000 miles between failures, way below the contract expectations of 20,800 miles.