Nassau Street Express·Jamaica Av Skip-Stop
The Z train is by far the most infrequent NYC subway line, and is a peak hour variation of the J train, allowing rush hour J and Z trains to alternate stops on the skip-stop portion of their lines between Marcy Avenue and Jamaica. Z trains skip 6 stops on this part of their line, J trains conversely skip 7 stops. (The numbers were at an even 7 stops for both J and Z trains until Alabama Avenue was made an all stop in 2014 to appease MTA employees going to the East New York Yard and Bus Depot).
The Z train operates just 6 round-trips per peak direction, rush hour. 6 trains leaving Jamaica Center during the peak of the AM rush hour, roughly every 10 minutes between 7:21am and 8:12am (arriving at Broad Street between 8:08am and 9:00am). 6 return trains leave Broad Street every 10 minutes between 4:54pm and 5:45pm (arriving at Jamaica Center between 5:45pm and 6:34pm). The reason that the Z train isn’t simply the diamond J is because it is not a peak-hour express variant of the J train running express while circle J trains run local, but a special rush hour variant of the J train, J trains and Z trains alternating the stops they stop at. It would be much more confusing to passengers during rush hour to have to differentiate whether they need a circle J or a diamond J, so simply calling the rush hour variant the Z train has been done for clarity.
The purpose of the Z train is relatively simple. It’s to solve the problem of the fact that there are only two tracks on the Jamaica Avenue elevated between Broadway Junction and Jamaica, with 13 intermediate stations. There is space to add a middle track on the more-modern dual-contracts portion of the elevated in Queens (that would cover 7 stations), but the portion of the elevated between Broadway Junction and Crescent Street dates back to 1885 and still has the original configuration for BRT elevateds with a narrow island platform between the two track line, and two very slow S-curves. In the 1960s the MTA proposed a flying express track, plus smoothing over the S-curves, there is are even the support beams for a guidway without tracks that rises up just before the Alabama Avenue station, to create an express track but this has never been built.
The first interaction of skip-stops on this stretch of line was instituted between 1959 and 1976 using different variations of the J (like JJ, and QJ) and KK trains, from 1974 to 1976 there were even two different J trains during peak direction rush hours, a J ‘A’ pattern, and a J ‘B’ pattern, which must have confused rides.
All skip-stop service was discontinued from 1976 to 1988 while the elevated line in Jamaica was cut back from 168 Street to Queens Boulevard and then 121 Street in 1985, before trains were re-extended to Jamaica along the Archer Avenue extension when it opened on December 11, 1988. It was in 1988 that the Z train was first operated with the same peak-direction service pattern and hours as today. The goal of the Z train and J/Z skip-stop service was to provide subway riders going from Jamaica to Lower Manhattan an incentive to choose the less crowded Jamaica Line over the E train that was operating at capacity. At the time skip-stop service from Jamaica to Broad Street took 48 minutes, compared to 54 1/2 minutes for local service, and 52 minutes for the E train. Those minutes saved on the J/Z skip-stop made it time competitive with the overcrowded E train.
The Z train has operated pretty much the same way since it was introduced in 1988. The only permanent service change was making Alabama Avenue an all stop in 2014 to appease MTA employees going to the East New York Yard and Bus Depot.
Other service changes were temporary, including running skip-stop in both directions during the Williamsburg Bridge reconstruction between Broadway Junction and Jamaica between May 1 to September 1, 1999, since rush hour passengers needed to take trains to either Broadway Junction or Jamaica to transfer to other subway lines to reach Manhattan. During the reconstruction of the M train branch to Middle Village from June 26, 2017 to April 27, 2018 all J and Z trains ran local between Broadway Junction and Marcy Avenue, because different shuttle bus routes connected at different stations.
The Z train has also been suspended for months at a time on at least 3 seperate occasions:
