Investigators are working to understand how hackers managed to breach Dallas Area Rapid Transit computers last weekend.
DART officials said the breach happened Saturday afternoon. The hack targeted customer communication and business processing tools, according to Morgan Lyons, DART spokesperson.
Trip planning tools and message boards at rail platforms remained affected Thursday, Lyons said. No customer or employee safety systems were compromised by the hack.
"We are continuing our forensic analysis of the attack to understand how it happened and how we can reduce the risk of another," Lyons said in a statement Thursday.
The hack may have resulted in brief service delays. Most computers were running normally Thursday.