Another Troubled Bridge

Just got this from TransitWorks:

To all Fairmount Line customers:

Due to the unscheduled closure of the Columbia Road Bridge there will be no commuter rail trains allowed to operate on the Dorchester Branch until the necessary repairs have been made. This is expected to last into this evening’s peak hour commute; however we anticipate that regularly scheduled service will resume for tomorrow morning.

Please note the following alternative arrangements:

Passengers going to Readville should use the Franklin line

Fairmount customers should take the Orange Line to Forest Hills and take the Rte 32 bus to Cleary Square.

Morton Street customers should take the Red Line to Ashmont and take the Rte 21 bus to Morton Street or alternatively the Orange Line to Forest Hills and take the Rte 21 bus to Morton Street

Uphams Corner passengers should take the Red Line to Andrew Station then take the Rte 16 bus to Uphams Corner.

Alternatively, if you prefer to travel by way of commuter rail from South station the following arrangements have been made:

Passengers traveling to Uphams Corner should take the Providence, Stoughton or Franklin Lines to Ruggles and take Bus 15

Passengers traveling to Morton St. should take the Needham Line to Forest Hills, then take bus 21.

Passengers traveling to Fairmount and Franklin should take the Providence or Stoughton Lines to Hyde Park, and then take Bus 32.

Can anyone help with a map of where this is? And am I right in thinking that on that day a couple of weeks ago, when a downed electric line at Ruggles forced trains onto the Dorchester Branch, they all passed over this bridge? Could that have anything to do with the sudden closure?