Slow-zone validation: outside evidence
I searched news, MTA press releases, MTA Weekender pages, Wikipedia (for dates it cites) and local papers. I used about 25 searches, so this is not exhaustive. Reddit and MTA board books gave little I could reach. “None found” means my searches turned up nothing, not that nothing happened.
| # | Zone | Evidence | What the source says (date) | Link |
|---|---|---|---|---|
| 1 | 7, 40 St → 46 St, Flushing-bound, from ~May 25, 2026 | Yes | From 10:30 a.m. Mon May 25, 2026 “through 2027”, Flushing-bound 7 skips 52 St and 69 St for platform rebuilds, and the MTA puts temporary platforms on the Flushing-bound side at 33 St, 40 St and 46 St. The start date matches to the day. The sources do not name a speed limit; temporary platforms next to a work zone are the likely cause. The 7 project also found bad steel under the line in 2025. | amNY, May 6, 2026; live notice, Sep 2026; MTA project page |
| 2 | N/W Queensboro Plaza → 60 St tunnel (from ~Jun 8, 2026); R Queens Plaza → 60 St tunnel (from ~Jun 1, 2026); Lex/59 → tunnel (from Jun 29, 2026) | None found | Nothing about a slow order in the 60 St tunnel in June 2026. Nearby work I did find: weekend R track replacement with R via 63 St (Mar 14–Apr 5, 2026); R via 63 St for track work on the weekends of Jun 12–15 and Jun 19–22, 2026; N/R/W track replacement between 57 St and 5 Av-59 St (Aug 2026 weekends, weeknights, and Aug 24–28 weekdays with W suspended). None of these is in the tunnel or starts on the detected dates. | Queens CB2 notice; Weekender Jun 12–15; Weekender Jun 19–22; Queens Gazette, Aug 5, 2026 |
| 3 | M, 21 St–Queensbridge → 63 St tunnel, from ~Dec 11, 2025 | Yes, but a route change | The F/M swap began Mon Dec 8, 2025: on weekdays 6 a.m.–9:30 p.m. the M now runs via 63 St and Roosevelt Island, and the F via 53 St. Before that, M trains did not normally use this stretch. The MTA also added peak M service. This is a new service pattern, not a speed restriction. | MTA F/M swap page; CBS, Dec 8, 2025; MTA board doc |
| 4 | R/W Whitehall St → Montague tunnel, Brooklyn-bound, from ~May 18, 2026 | Partial (timing only) | On the weekend of May 15–18, 2026, late-night R did not run between Whitehall St and 59 St (Brooklyn) “because of electrical work”. The same thing happened on Apr 24–27, 2026 for “accessibility, signal, and track work”. The detected start is the Monday after the May weekend. No source says the work was in the tunnel or left a slow order. | Weekender May 15–18, 2026; Weekender Apr 24–27, 2026 |
| 5 | D Norwood–205 St → Bedford Park Blvd, from ~Apr 21, 2026 | None found | Nothing for April 2026. Norwood–205 St is the D terminal. Trains arrive on one track, run east to a tail track and come back on the other. ADA work there is only “proposed” in the 2025–29 plan. | Wikipedia: Norwood–205 St |
| 6a | 3, 135 St → 145 St, Jan 31–Sep 2, 2025 | Partial (terminal work) | Accessibility work at Harlem–148 St, the 3’s terminal one stop north. From about Feb 2025, some early-morning and late-evening 3 trips ran to 137 St–City College instead, and some evening trips ended at 135 St. 137 St trips ended Jun 8, 2025. The ramp was about 80% done in Sep 2025 and opened in May 2026. These sources describe work at the terminal, not a speed limit between 135 and 145 St. | Wikipedia: 3 service; Manhattan Times, Sep 30, 2025; MTA press release |
| 6b | 3, 135 St → 145 St, Jan 14–Jun 30, 2022 | None found | Nothing for 2022. In early January 2022 the 3 was hit by crew shortages from COVID, but that does not explain a five-month slowdown. | Patch, Jan 3, 2022 |
| 7 | 6 Av 42 St–Bryant Park → 47–50 Sts, Aug 28, 2023–Jan 30, 2024 | Yes, but a reroute | 63 St line track replacement started Mon Aug 28, 2023 and ended Apr 1, 2024. Weekday F trains ran via 53 St, so they turned off at 47–50 Sts onto the E line, and M trains ended at 57 St. The start matches to the day. The end does not: the project ran two more months. This looks like merge and turn-back congestion, not a slow order. | MTA press release; MTA, service restored Apr 1, 2024 |
| 8 | 6, 51 St → Grand Central–42 St, Jun 17–Nov 11, 2022 | None found | Only one-off incidents: third-rail damage at Astor Pl (Jul 11, 2022) and a train hitting debris at 51 St (Aug 12, 2022). Neither explains five months. | 1010 WINS, Jul 12, 2022; NBC NY, Aug 12, 2022 |
| 9 | B/D/F/M Broadway–Lafayette → W 4 St (uptown), May 15–Jun 16, 2023 | Yes (strong) | Switch replacement near W 4 St on the uptown local/express crossover, from May 15 to Jul 3, 2023. The MTA said uptown B/D/F/M trips would be “scheduled to take an additional two minutes”. The start matches to the day. The detected end is about 2.5 weeks early. | MTA press release; Gothamist, May 14, 2023 |
| 10 | 2/3 Wall St → Clark St, May 5–Oct 3, 2022 | Yes, but a station reopening | Clark St station was closed from Nov 3, 2021 to May 4, 2022 for elevator replacement, and trains ran through without stopping. It reopened May 4. The detected start (May 5) is the next day, so the “slowdown” begins when trains started stopping there again. I found nothing for the Oct 3 end. | MTA, reopening; Brooklyn Eagle, May 5, 2022 |
| 11 | J/Z 121 St → Sutphin Blvd, Mar 4–Aug 26, 2026; J Cypress Hills → Crescent St, Apr 13–Sep 15, 2026 | Partial | A J track replacement program ran from early March 2026 “through the third quarter of 2026”. During it, Manhattan-bound J trains skipped Chauncey, Halsey, Gates and Kosciuszko midday, Tue–Fri. That is in Brooklyn and in the other direction. There was also weekend track replacement between Jamaica Center and Crescent St (Apr 17–20, 2026) and between Crescent St and Broadway Junction (May 17, 2026). The 85 St–Forest Pkwy station work slipped from Aug 2025 to the end of 2026. The dates fit; the exact place and direction do not. | NY Post, May 26, 2026; Weekender Apr 17–20, 2026; Weekender May 15–18, 2026; Queens Chronicle, Aug 13, 2026 |
| 12 | B/Q Church Av → Parkside Av, Nov 29, 2024–Jun 12, 2025 | Yes (start), partial (end) | Church Av accessibility work. B trains ran local between Prospect Park and Kings Hwy from Aug 5, 2024 to Feb 24, 2025. Southbound trains skipped Church Av until Nov 23, 2024, then northbound trains skipped it until Feb 17, 2025. Crews built a mezzanine over the tracks while trains ran; it opened Nov 10, 2025. The detected start matches the switch to northbound work. The Jun 12 end does not match a found event, though new timetables took effect Jun 8, 2025. Note that the B stops at Parkside only when it runs local, so the B part of this zone exists only because of the reroute. | Wikipedia: Church Av; Wikipedia: B service; Gothamist, Aug 5, 2024; amNY, Nov 25, 2025 |
Summary
Section titled “Summary”Count. I found a known cause whose start date matches for 7 of the 13 zone-periods: 1, 3, 6a, 7, 9, 10 and 12. Two have weaker matches (4 and 11), where the dates fit but the place or direction is off. I found nothing for four: 2, 5, 6b and 8. Only zone 9 has the MTA saying in plain words that trains would be slower (2 extra minutes uptown). Zone 1 (temporary platforms) is the most likely to be a true speed restriction. End dates match less often than start dates; zones 7, 9 and 12 all end at a different time from the work.
Likely false positives, or real slowdowns that are not speed restrictions:
- Zone 3 (M, Dec 2025): the F/M route swap on Dec 8, 2025. The M began using this track on weekdays, so the change is in the service pattern, not the track.
- Zone 10 (Clark St, May 2022): the station reopened May 4, 2022. Trains began stopping again, which adds time.
- Zone 7 (6 Av, Aug 2023): the F reroute via 53 St during 63 St track work. This is merge congestion, not a slow order.
- Zone 6a (3 line, 2025): work at the terminal, with short turns and reroutes to 137 St.
- Zone 12, B part: the B stops at Parkside only while it ran local.
- Zone 5 (D at Norwood): I found no cause. Because it ends at a terminal, the result may depend on how trains turn back there. I have no source on this; it is worth checking against timetable changes.
A filter that drops segments whose service pattern changed (new route, reopened or skipped station, or a reroute onto local track) would remove 3, 10, and parts of 7 and 12.
Known 2022–2026 events a good detector should catch (some are closures, which may show as gaps, not slow zones):
- Concourse line express track closed Jul 2, 2022–Jan 23, 2023; the D ran local in the Bronx. (Wikipedia: D service)
- J/Z cut back to 121 St for Archer Av track replacement, Jul 1–Sep 19, 2022. (MTA; MTA, completion)
- W 4 St uptown switch replacement, May 15–Jul 3, 2023 (zone 9, found). (MTA)
- 63 St line track replacement, Aug 28, 2023–Apr 1, 2024 (related to zone 7). (MTA)
- J/Z 75 St and Woodhaven Blvd station work: Jamaica-bound trains skipped them Feb 26, 2023–Jan 2024; later phases ran into mid-2025. (Wikipedia: J/Z service)
- Church Av B/Q work, Aug 2024–Feb 2025 (zone 12, found).
- Rockaway line closed Jan 17–May 19, 2025 for the Hammels Wye and South Channel Bridge rebuild. Expect slower running just after reopening and on later work weekends. (amNY, May 19, 2025)
- 7 line structural and platform work, 2025–2027. Manhattan-bound trains skipped four stops May 11–22, 2026 (zone 1 is the Flushing-bound phase). (amNY)
- J midday skip-stop track replacement, Mar–Q3 2026, Manhattan-bound in Brooklyn. Your detector found Jamaica-bound zones but not this stretch, which is worth checking. (NY Post)
- Upcoming: J local Marcy Av–Myrtle Av on weekdays 10 a.m.–3 p.m. from Oct 13, 2026 for switch replacement. (amNY, Sep 29, 2026)
Systemwide timetable changes (for example Jun 8, 2025 and Nov 2, 2025, both cited on Wikipedia) can shift run times on many segments at once. Check whether any zone starts or ends on a timetable date.