PHILADELPHIA — A faulty weld that attaches a plate to a weight-bearing beam is at the foundation of the problem that has put more than 100 SEPTA  rail cars out of service.

The Philadelphia Inquirer reports that acknowledgement was made by Hyundai Rotem, the company that built the cars. The company's development manager, Andrew Hyer, says how it decides to weld the material may make the difference.

Hyer says the weld work was designed and executed by HiCorp., a company subtracted by Hyundai Rotem. A woman answering the phones at the company says no one would comment.

SEPTA sidelined a third of the coaches in its regional rail system earlier this month after defects were found in the suspension systems.

Sign up for the NJ1015.com Newsletter

Get the best of NJ1015.com delivered to your inbox every day.

(Copyright 2016 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed)