The 4 and 5 subway trains in Brooklyn are not running this weekend, with service on both lines, along with the 6 in Manhattan, being suspended south of Grand Central.

The interruption started at 11:30 p.m. Friday and will continue until Monday 5 a.m.

According to the MTA, the suspension is necessary so that crews can replace the concrete under some of the switches, which they say is important for structural stability. This also helps protect the system from leaks and corrosion.

"When the people are out (at night) and they're shopping and partying, it's going to be a zoo," predicted Derek Durham, who lives in Crown Heights and takes the impacted lines often.

"I don't know what I'm going do now," said Jennie Wasserman, who lives in New Jersey and was visiting a friend in Crown Heights this weekend. "That's New York right? Always keeping you on your toes."

"You don't want to do it in winter time. Summertime now, do it, get it out of the way so we can ride smooth in September," Durham added, explaining that he would rather not deal with service interruptions in the cold.

However at the Franklin Avenue-Medgar Evers College station, a News 12 crew did not see any signs or indications outside the entrances, or down near the gate warning commuters about service disruptions. There was only a small note on the digital board next to the ticket booth. Many riders only seemed to be learning of the suspension when it was too late.

That included Wasserman.

"I guess I could have looked on the app, but I just was...just counting on a train like the 4, 5 being available," she said.

Zipporah Meredith, who lives in Crown Heights, also said she had no idea, and only found out on her way home from work overnight.

"The 4 train was supposed to be here in like four minutes, and then it just switched over to the 3 train," she said.

The 2 and 3 trains do make all the same stops in Brooklyn as the 4 and 5, just with more local stops as well, and those are still running.

The MTA also says this weekend, the 3 will keep running all the way to the final stop at New Lots Avenue. This includes the overnight hours, something that is not normally done. Riders agreed that change definitely helps with the suspensions.

However, the routes of the 2 and 3 are different from the 4 and 5 once they get into Manhattan.

Because of that, Wasserman said it's going to impact her.

"It's going to take me a lot longer to get back to Jersey. I don't know, I'm going to have to figure it out," she said.

Aside from this weekend, the same suspensions will also happen next weekend to allow the MTA to finish the work.