With a plan to mount the cables along the wall, we then asked ourselves whether removing all of the bench wall — a time-consuming, fraught and expensive endeavor — was necessary. In fact, inspections have indicated that, at most, 40 percent of it is damaged, and we have proposed demolishing only the heavily damaged sections, leaving intact the structurally sound parts.

The purpose of the bench wall in the new plan is solely to provide a pathway for access by maintenance workers and an emergency exit.

The parts to be removed would be replaced with a fiberglass or steel walkway that is considerably easier to install than a new concrete structure. Proven fiber-reinforced polymer — a solution used to strengthen critical load-bearing infrastructure such as bridges — would be used to further strengthen remaining bench wall.

In replacing only the damaged sections, the work can be done in increments on nights and weekends — and we would avoid the total shutdown of the subway line. Our plan would also reduce the amount of hazardous silica dust that results from demolition of the bench wall. We recommend the whole process be monitored by an external agency to further ensure safety.

A high-tech laser system, known as Light Detection and Ranging, or Lidar, would be used to monitor the structural integrity of the bench wall and the tunnel itself. Smart fiber-optic sensor cables installed along the structure could detect any shifts or cracks, enabling the transit agency to identify, then repair or remove bench wall as needed in the years to come.

All other upgrades in the original plan — increasing pump capacity, renovating track and stations, enhancing flood resiliency — remain in our plan.

We are aware that our proposal is a unique approach to the tunnel restoration. Some have referred to it as a “patch job” — but nothing could be further from the truth.