Bronx subway riders on the 6 train can now start counting down the days when three of their stations will get countdown clocks, telling them when the next train will arrive. New York City Transit is promising to install the digital signs at the Longwood Avenue, Brook Avenue and 149th Street stations by year's end. The rest of the 6 line and all other numbered lines will get the countdown clocks by the end of 2010. Currently, only the L and the 34th Street bus corridor have the clocks. Software development glitches have delayed their installation in other parts of the system. The letter lines will take several more years. Bus riders can look for the clocks next on the 49th and 50th Street stops in Manhattan, though no launch date has been announced.