A downtown section on Line 1, the Yonge-University-Spadina subway line, is expected to be closed this weekend.

The TTC will be conducting signal upgrade work between Bloor-Yonge to St Andrew stations and oncoming trains will terminate at those stations, the transport authority said in a news release Wednesday.

The TTC said it will operate 47 shuttle buses on Yonge St. between Rosedale and King stations and over to St Andrew station.

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Union station is expected be closed and there is no access from the subway station to the main train station. Commuters going to the Air Canada Centre will need to walk from King or St Andrew stations or take Bus 6 on Bay St.

Fans going to the Rogers Centre for Blue Jays baseball games can walk from St Andrew station or take Streetcar 510 on Spadina Ave., which currently terminates at King St. because of construction and then walk or board a replacement bus to continue south.

TTC said the signal upgrade work is part of its modernization efforts.

“The existing signals, relays, wiring and cabling equipment, much of which is approaching 60 years of age, need replacing as their continued failure significantly impacts service,” the transport authority said.

TTC is also expected to provide Wheel-Trans buses to accommodate seniors and people with disabilities.

Customers can also use streetcars 504 on King St. or 505 on Dundas St. to get downtown. Both routes terminate at Broadview and Dundas West stations on Line 2 (Bloor-Danforth).

Regular subway service is expected to resume on 6 a.m. on Monday.