 Meanwhile, the already heavily damaged stairs continued to deteriorate due to the heavy vibrations caused by construction of the permanent PATH station, the World Trade Center Memorial and 1 World Trade Center on the site.In January 2007, the Lower Manhattan Development Corporation (LMDC), according to "Real Estate Weekly," rejected a plan proposed by structural engineer Robert Silman, who functioned as an independent consultant, to move the staircase in its entirety.Silman estimated the move would cost somewhere between $500,000 and $700,000 to complete.