7:43 AM, Friday, November 15, 2019:
Three separate incidents happen:
1. There is an unauthorized person in the express tracks at 23 St/8 Av.
2. There is a door problem at a train in the northbound express track at 34th St/Herald Square.
3. Similarly, there is a track fire at the northbound track in Grand St, and it has spread to the other track, forcing the station to close.
Reroute away!
Also, you can't fit and into the local tracks. Similarly, on Culver isn't going to work without having to reduce the headways or rerouting a line, and is also on 6th Ave, this would cause considerable delays.