Metra trains were at a standstill on three commuter lines for part of Monday morning, with service on two of them starting to resume by around 10 a.m., according to an agency spokeswoman.
Services on the North Central Service, Milwaukee District North, Heritage Corridor lines and part of the Union Pacific Northwest line were halted for a time, according to Metra spokeswoman Meg Reile.
Reile said railway company Canadian National had an issue with its train control system, causing the stoppages.
The North Central Service and Heritage Corridor lines operate on lines owned by Canadian National, according to Reile. The Milwaukee District North and Union Pacific Northwest lines cross Canadian National lines.
Reile said the issues started around 5:20 a.m. Monday.