[k1052]

MTA considered Cuomo's plan years ago and it was shot down for safety and service issues.

The transit agency has come under intense criticism for not thinking of the idea sooner, but officials did closely examine an option much like the one Mr. Cuomo is pursuing in May 2014. Engineers warned that mounting heavy cables to the wall of a nearly century-old tunnel under the East River between Manhattan and Brooklyn could damage its lining, according to the documents.

“Excessive anchor bolt penetrations for installing critical cables may damage the concrete lining and induce leakages,” according to a report by the transit agency and Parsons Brinckerhoff, an engineering consultant now known as WSP that is leading planning for Mr. Cuomo’s alternate plan.

Instead of closing the subway tunnel for 15 months, the new plan would limit construction work to one tube at a time on nights and weekends over a longer period of time. But the report raised concerns that the construction work could create silica dust, a hazardous mineral that would be difficult to remove during a short weekend closing. Exposure to silica dust can damage the lungs.

The engineers also said there was a “high risk” of not being able to restore train service on time every Monday morning.

Also the repair is expected to have a life of maximum half as long. Certainly possible it lasts that long but also possible the lifespan is FAR shorter if it doesn't work. Nobody knows.

Workers would remove damaged parts of the bench wall and secure other parts with a substance known as fiber reinforced polymer that could last 40 years. Rebuilding the bench walls, as the original plan called for, could last more than 80 years

https://www.nytimes.com/2019/01/15/n...a-subway-.html

The original plan, while more disruptive, is more conservative engineering and wiser in terms of dollars spent. Given the experience the MTA gained in the other tube reconstructions they probably would finish ahead of schedule. This whole plan looks really irresponsible.