on Fri Jan 11 19:03:35 2019, in response to Re: New MTA statement on L-train project, posted by #5 - Dyre Ave on Fri Jan 11 17:32:15 2019.
The tunnels have a alkaline-silica reaction (sea water is reacting with the cement in the shoulder walls) causing it to expand. Covering the shoulder walls with fiberglass does nothing to prevent this from continuing. The walls will need to be replaced. By doing a cosmetic fix, the urgency of actually doing the work disappears, for perhaps 10-15 years. The it LOOKS like the tunnels are fine, when in fact they are not, and some folks get credit for saving lots of money and fixing the problem.