Officials released an update on construction for the Valley Line LRT Thursday morning – 2018 is expected to be the busiest year for the project, but an unexpected object has held up construction for one of the major components.

TransEd said construction on the line into southeast Edmonton is on schedule, save for a setback caused by something crews found in the river valley.

Nine metres under the riverbed, crews found something that has set back construction of the Tawatinaw Bridge – an LRT bridge with a pedestrian walking path below.

“We encountered an unknown object, it turned out to be a large concrete mass that has put us behind schedule,” Dean Heuman with TransEd said Thursday.

Officials said they can’t move or break the slab of concrete that they estimate could be as big as a car. Plus, they’re not sure how old it is or why it’s there.

TransEd said the bridge will be built on time, but the pedestrian pathway will be delayed.

As for construction on the rest of the line, drivers will notice a number of detours throughout the spring and summer near construction sites.

Officials believe Connors Road and some roads in the downtown core will see some of the biggest traffic disruptions.

The lane control signals on Connors Road will be out of commission until the project is done – that will impact traffic into downtown.

“Come in on 98 Avenue, that is going to be the number one major detour, so start to plan now,” Heuman said.

Plus, the traffic circle in Bonnie Doon will eventually become a four-way intersection – although that change will not take place until 2019.

Details on Valley Line LRT construction can be found on the project’s website.

With files from Jeremy Thompson