UPDATED 02/21/11 9:41 a.m.

CHICAGO (STMW) -- Signal problems on Metra's Union Pacific line caused delays for commuters Monday morning.

Trains were being delayed between 15-20 minutes due to system-wide signal computer problems on the Union Pacific Railroad, while some Milwaukee North were also affected, according to a Metra service advisory.

Metra spokesman Michael Gillis said the delays began sometime after 6:30 a.m when a computer failure caused problems to their signal system.

Delays were also reported on the Milwaukee North line because the line crosses over onto UP tracks at a crossing, Gillis said.

The problem was corrected at some point before 7 a.m. and no delays were being reported at 9 a.m.

(Source: Sun-Times Media Wire © Chicago Sun-Times 2011. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)