Federal data revealed that New Jersey Transit trains were involved in over 160 accidents since 2011, costing more than $4.8 million in damages to tracks and equipment. The data showed that NJ Transit had to pay over $500,000 to settle 183 safety violations.

The safety violations include drug or alcohol abuse in employees and violations of railroad operating rules, the Federal Railroad Administration report said. Between 2014 and 2015 NJ Transit settled $70,000 worth of safety violations.

A U.S. official told the Associated Press Saturday officials detected several rail safety violations while auditing the NJ Transit months before Thursday’s crash that left over a 100 people injured.

The audit, the source told AP, began in June in which authorities found “dozens of safety violations.” These violations had to be fixed immediately the administration noted. The agency was fined at the end of the audit and is working with the administration to set the violations right.

According to the data, there have been 25 accidents in 2015 and 10 in the beginning of 2016. None of the accidents caused injuries or deaths and occurred at low speeds.

On Thursday morning, a commuter train sped into the Hoboken train station, crashing into the depot’s wall and killing one woman and injuring over a 100 people. Local reports said the train was travelling at a speed thrice the typical 10 miles per hour.

The engineer behind the train involved in the crash was identified as 48-year-old Thomas Gallagher who is reportedly cooperating with authorities in the investigation.

Reports said that the train was not equipped with Positive Train Control, a safety system that could have prevented the crash by automatically slowing the train.

“We know that it can prevent accidents,” Bella Dinh-Zarr, vice chairman of the National Transportation Safety Board, said. “Whether it is involved in this accident, that is definitely one of the things that we will look at carefully.”