Subway service on the W line was suspended most of the day Wednesday after a vandalism spree on Tuesday evening.

The MTA said a vandal or vandals smashed 78 windows on 35 trains from the inside. It appears it happened while the trains were in service.

Service was suspended overnight Tuesday and for most of the day Wednesday up until the evening commute.

So many windows were damaged that officials said they were running out of spare glass to make repairs.

By around 11 a.m. Wednesday, 25 trainsets had been repaired, but hundreds of thousands of commuters were impacted by the damage before service resumed shortly after 5 p.m.

The damage also impacted service on the B, D, N, F and Q lines. The MTA said it was focused on making repairs and getting service back on track.

Officials estimated the repair bill could run into the six figures.

“Pissed off, can I say pissed off? I mean, seriously, we work, I have train crews sitting in that break room right now who don’t have W trains to run — they want to be out there,” said NYC Transit President Richard Davey. “When this stuff happens, it frustrates the hell out of me and I know it frustrates the hell out of our commuters. Because they just want to get home, they want to get to work, they want to get around the city.”

The MTA said it was using windows from unused trains and posting extra officers on subway platforms.

Police said the video system in the subway system is vast and robust and they hope it will prove helpful.

Anyone with information is asked to tell a police officer or MTA employee, or call NYPD CrimeStoppers at 1-800-577-TIPS.