Metrolinx has confirmed that its construction work at the new GO station on Dundas Street West covered TTC tracks in debris.

The debris caused the service suspension on the Bloor line that began during rush hour between St. George and Keele stations on Tuesday. Service resumed around 3 p.m.

TTC officials said groundwater started seeping a hole in the subway tunnel on Tuesday. The debris mixed with the water resulted in mud. The hole was found last week.

“Something changed today about the groundwater being found its way into the hole,” TTC deputy chief operating officer Mike Palmer said at a noon-hour news conference.

The TTC is planning on a permanent fix, but Palmer said it will take a few days to work out and hopes to have permanent fix in the next few months.

“This afternoon, we will reopen with a semi-permanent fix,” Palmer said.

The new GO station on Dundas Street West is part of the Union-Pearson Express train.