After a six year absence, the W train is back and running today, with service between 6:30 a.m. and 11 p.m. on weekdays. Here's what it means for people who have been taking the N, R and Q trains:

- The W serves as a local train in Queens and Manhattan on weekdays, operating between Astoria-Ditmars Boulevard and Whitehall Street-South stations.

- The N will run express in Manhattan on weekdays and local during late nights and on weekends. It will stop at 49th Street at all times.

- The Q will only run in Manhattan and Brooklyn now, and service will be between 57th Street-7th Avenue and Coney Island. The Q will remain an express train in Manhattan, and if you want to get to Queens, take the N or W.

- The R will now also run in Manhattan during late night hours, with service after 11:30 p.m., between Bay Ridge-95 Street and Whitehall Street-South Ferry.

The MTA has a very handy map and infographic outlining the changes, which are in place to get ready for the Second Avenue Subway's return. The W line was eliminated in 2010 during a round of MTA "doomsday" cuts, and MTA board member Andrew Albert said earlier this year that the W should be more fully restored, "I will still put in a pitch for, during rush hour, extending the W down to say, a Bay Parkway terminus. Having the R the only train along local stations along 4th Avenue and rapidly developing areas of Southern Brooklyn is not enough."