If you are riding the subway tonight and the countdown clocks don't appear to be working, DON'T PANIC. That is on purpose. The MTA is going to be doing tests on the system and its back-up.

In order to upgrade their software, the MTA says that their Countdown Clocks and the mobile app Subway Time will not be available starting after the evening rush hour (about 9 p.m.) until shortly before morning rush hour tomorrow. For what it is worth? The MTA apologizes for the inconvenience.

Don't worry guys, we've been through this before.