As more and more people move along the M train the limitations of the current junction at Myrtle-Broadway will soon need to be addressed. The MTA is undergoing a rebuild of the viaduct which hold the track but it will not address the bottleneck. Here’s how the MTA could do so.
Starting in the summer of 2017 the MTA will shut down service along the Myrtle Ave Line (M train) from Broadway to Metropolitan Ave. The closure is so the MTA can rebuild a crumbling bridge and viaduct to allow for better service once the Canarsie Tubes of the L train are shut down for Hurricane Sandy related repairs. While this relatively small project is important for keeping the system moving it is really only a band aid on a larger issue: the BMT Jamaica and Myrtle Ave Lines have some of the oldest continually operating track structure in the entire NYC Subway and the junction at Myrtle Ave is a bottleneck along two lines which are seeing continued ridership growth due to the popularity of both Bushwick and now Bedford-Stuyvesant. This is a missed opportunity by the MTA to not just rebuild aging infrastructure but do so which eliminates a crucial bottleneck and expands capacity along both lines.
Both the Jamaica Line (J/Z trains) and the Myrtle Ave Line originally date back to the late 1880s when Brooklyn was still its own independent city and was growing rapidly. What we have with the M train today is only a vestige of a longer line which continued down Myrtle Ave to downtown Brooklyn and over the Brooklyn Bridge into Manhattan. The Myrtle Ave Line eventually had direct connections to many of the other Brooklyn elevated lines which have now been torn down as well. In 1914 the direct connection between the Myrtle Ave Line and the Jamaica Line at Myrtle-Broadway was opened allowing dual services to run, one via the Brooklyn Bridge and one via the Williamsburg Bridge. Originally a connection was planned from Chambers St station with the Brooklyn Bridge which would have allowed elevated lines to loop back into Brooklyn offering a variety of services. Such a system never came to pass as the new subways proved more popular than the old elevated lines which the city soon began to replace. After WWII the population of central Brooklyn declined and so too did ridership on the Myrtle Ave Line which ended downtown service in 1969. The elevated structure from downtown Brooklyn to Marcus Garvey Blvd was town down and all service east of Broadway ran exclusively to Manhattan via the Williamsburg Bridge.
As the popularity of Williamsburg and Bushwick has grown over the last 20 years so too has ridership. In 2010 the M train was rerouted from downtown to 6th Ave which has proven very popular and an alternative to the crowded L train. This is where the bottleneck at Myrtle-Broadway starts to become an issue. As more trains are needed to account for ridership growth the at-grade junction keeps capacity limited. This wasn’t as much of an issue when the M train terminated at Broad St since the J/Z provided additional downtown service. But the M now continues on to Forest Hills via the notoriously congested Queens Blvd Line. Due to the bottleneck M trains can only be scheduled at about 8 trains per hour leaving time for up to 5 more trains per hour available if the bottleneck was removed (theoretically there could be as much as 15tph but due to congestion along 6th Ave and Queens Blvd realistically the max is 12 or 13 tph). Not only would this mean better service for Williamsburg and Bushwick but also for Queens as well.
The MTA is planning on rebuilding the concrete viaduct that connects the Broadway Line with the Myrtle Ave Line but not eliminating the bottleneck. This bottle neck can be eliminated by building a new flying junction between the Flushing Av station and Myrtle Ave station. The current local tracks would be moved outward so that two new tracks can be added between. These two new tracks would connect to both the local and express tracks. As they approach Myrtle Ave the new tracks would rise up and a new upper level station would be built over the existing Myrtle Ave station, though slightly to the west. This new station would mirror the existing station with three tracks and two island platforms. The remnants of the old Myrtle Ave El would be removed south of Broadway so that the new tracks could be extended along the abandoned trackways as they turn down Myrtle Ave. The trackways are still in good shape as they are connected to the existing junction structure. This new upper level station would serve Myrtle Ave trains exclusively and the reason for the mirrored design is so elevators could be installed to connect the platforms. Additionally a third track could be installed between the new Myrtle upper level and the existing Myrtle Ave Line. A third track was installed between Central Ave and Wyckoff Ave but was only used for storage and was removed in 1946. With an increase in trains per hour a third track may be useful for turning trains at Wyckoff Ave at rush hour or for emergencies.
A dual level station like what I am proposing has precedent throughout the NYC Subway. At West 8 St on the Brighton Beach Line (Q train) and the Culver Line (F train) each train has a separate level with the Q train rising up to the upper level exactly how the new Myrtle Ave connection would do so. Historically at Gun Hill Rd on the White Plains Line (2/5 trains) there was a similar connection with the now demolished 3rd Ave El with each line on a separate level and then merging north of the station. Not only does this design eliminate trains having to pass in front of one another but in the case of Myrtle Ave the sharp 90 degree curve would be eliminated so trains can turn faster and safer, not to mention the reduced wear and tear as well as noise.
The repairs the MTA is undertaking next year are part of a larger recovery plan and not part of any long range strategy. As time is of the essence when it comes to the Canarsie Tubes I cannot fault the MTA for deciding to go for the quick option for rebuilding the Myrtle Ave connection. But as more and more people move into central and northern Brooklyn the limitations of our existing infrastructure are becoming apparent.