The LRT in Edmonton will be shutdown from the start of service Sunday till noon for system-wide signal testing.

The shutdown is one of several scheduled in the coming months to accommodate Thales Canada's request to test its signalling system in the field.

Thales presented the city with a schedule to test the system last month after administration issued a notice of default — a necessary legal first step toward contract termination — on its $55-million contract with the signalling company.

The $600-million Metro Line has been plagued by problems since it opened more than a year late in 2015.

Thales said it had developed a "detailed roadmap" to complete the project, which it would implement with cooperation from the city.

The city said it chose the least disruptive time to allow Thales to carry out its testing.

A replacement bus service will be offered to riders from the start of service until noon with buses running every seven to eight minutes during the closure.

Replacement service locations can be found here.