PHILADELPHIA (CBS) — Tuesday’s train collision is the latest in a string of train-related issues for SEPTA over the past seven months.

4 Injured After SEPTA Trains Derail Near 69th Street Terminal

Last July, the transit agency pulled a third of its regional rail fleet after structural defects were discovered.

Inspectors found cracks under 120 Silver-Liner Five cars.

Earlier this month, inspections revealed cracks in 58 Market-Frankford Line train cars.

SEPTA was forced to pull those trains out of service for repairs.

And Tuesday, the crash near 69th Street Station which left four people injured, one critically.

Two trains collided on one track and a third car was impacted on a separate track.