When it rains, it pours on the T: More Government Center Garage problems shut Orange, Green Lines downtown

The T shut the Green and Orange Lines downtown again this evening after another "structural issue with the Government Center Garage."

Green Line service has been replaced by buses between Lechmere and Government Center. The Orange Line is shut between North Station and Back Bay, "until further notice," the T says.

Boston Police report portions of Congress Street, Surface Road, New Chardon Street and Sudbury Street will be shut to both motorists and pedestrians.

In a statement, the T said:

This afternoon, HYM Construction, the contractor demolishing the private Government Center Garage, advised the MBTA that the garage’s support columns that pass through MBTA tunnels near Haymarket station are severely deteriorated, creating an unsafe environment in the tunnel area for Green Line and Orange Line trains to operate through. The condition of these columns requires the suspension of Green Line and Orange Line rail service effective immediately in the tunnels beneath Haymarket station.

In March, the T had to do something similar after part of the garage collapsed, killing a construction worker, during work to take what's left of the garage down to make way for an office tower.

In their own statement, developers National Real Estate Advisors and The HYM Investment Group say the problem is unrelated to the garage demolition - and that just one column is involved:

A subsurface column in proximity to the Green and Orange Lines was identified as compromised from years of water damage. The condition of this column is unrelated to the demolition work at the Government Center Garage.

MBTA General Manager Steve Poftak said HYM can expect a bill:

This service disruption as a result of HYM’s project is unacceptable and the MBTA will seek to hold HYM Construction accountable for all costs associated with this event. Riders’ safety is our top priority and unfortunately, as a result of this private party’s project, we must divert trains until the tunnels can be inspected and cleared by independent experts.

The latest garage woes are themselves the latest problems to beset the T this month. Other problems have included Green Line trolleys colliding and coupling, a runaway Red Line train, some scathing federal reports on T operations, cutbacks in Red, Orange and Blue Line service due to those reports and the need to pull all the new Orange Line trains after a battery in one of them exploded.