I used to live on the Northside of Williamsburg (North 6th between Driggs and Roebling) and got very familiar with the L Train for a few years.  So I know all about the trials and tribulations of that line.

New York 1 reports that efforts to computerize it are now $30 million over budget and a year behind schedule.

The Transit Authority doesn’t have enough new trains to handle the
surge in ridership on the line, forcing the agency to bring back some
of the older trains. That means re-installing the old signal system so
they can run on the same tracks as the new trains. Another batch of new
trains won’t be available for at least a year and a half.

The high-tech trains were first introduced four years ago which meant the elimination of  conductors, Conductors were removed but then brought back in September.