Train service may not be restored for several days, Skokie village officials said.
PHOTOS: Embankment collapses beneath CTA Yellow Line tracks
The embankment gave way late Sunday as the Water reclamation district was digging a new deep trench for a box culvert to handle the delivery and exit of wastewater at the treatment plant next door. Interlocked pilings were driven deep into the embankment wall and cross bars were in place to prevent the collapse. Those didn't work, and no one is certain why.
"It was an engineered system and it was calculated to be secure. And for whatever reason, we don't know, that system gave way and dirt sloughed off the train system," David St. Pierre, Metropolitan Water Reclamation District, said.
The slide occurred a short distance west from the dig, rendering the tracks unstable. The task at hand: shoring up the embankment. Officials said it will take about 18 hours to get the power lines back up. There's no estimate on how long the CTA Yellow Line will be without service.
Shuttle buses are running between the Oakton, Dempster and Howard stations. Officials also recommend commuters take the #97 Skokie bus if possible.
About 2,900 passengers take the Yellow Line on the average weekday.