The incident occurred on Thursday, March 17, at around 4:00 a.m.. PKP Polskie Linie Kolejowe:

Malfunctions have occurred in railway control equipment at several local control centers responsible for managing railway traffic. The situation requires the equipment to be secured in the field and additional work by employees.

The effect? The company says:

Train services are being changed, in some cases by more than several dozen minutes. Trains may be canceled, replacement bus services may be introduced, or trains may be rerouted.

It adds:

A special team made up of infrastructure manager and railway operator representatives is working to organize train traffic on an ongoing basis. Announcements about the current situation are being made at stations and stops.

A local control center (LCS) is a place from which employees manage train traffic using computer systems at stations and on railway lines ranging from several to several dozen kilometers in length.