By Alexandria Hoff

PHILADELPHIA (CBS) — All eyes are on the battleground state of Pennsylvania, and a record number of mail-in ballots are being processed right in Philadelphia.

The Pennsylvania Convention Center is a crucial location where a record number of mail-in ballots are being processed. A lot of heavy machinery is doing a lot of work inside of the Convention Center.

According to Pennsylvania’s secretary of state, the commonwealth has so far received over 2.5 million mail-in ballots.

Philadelphia was the county with the highest number requested.

The ballots that had already been mailed in or dropped off had remained unopened for weeks, until 7 a.m. Tuesday, when the operation to count those votes kicked off inside the Convention Center.

City officials say 350,000 to 400,000 ballots are being counted at the Convention Center, and with a volume like that, city commissioners do not expect final results to come in until later this week.

The results of 75,000 mail-in ballots have so far been posted to the city’s website, results.philadelphiavotes.com. The counting machines can process about 10,000 ballots per hour not account for breaks or shift changes.

More than 150 people are working eight-hour shifts and they’ll work 24-7 until every vote is counted, officials said.

“Each part can only go as quickly as any other part is going,” City Commissioner Al Schmidt said. “We have an absolute army of people who work for our department directly that the rest of the city government has been extremely helpful in pitching in and pulling people from all different parts of city departments to help in this effort and if you see down there, it’s just a nonstop undertaking.”

Since this is the first year for no-excuse mail-in voting, and since the operation is so massive, officials warn the final count could take days.

One resource pushed by Gov. Tom Wolf is the VotesPA website to track the counting of mail-in and absentee ballots. Results began coming in around 8 p.m.

On Tuesday evening, Wolf released a video urging Pennsylvanians to remain calm and stay united on election night and the days ahead.

“Across the state, dedicated county workers are ready to tirelessly make sure everyone’s vote counts,” Gov. Wolf said.  “But counting that tremendous number of ballots will take more time than we are used to. We may not know the results today, but I encourage all of us to take a deep breath and be patient. What is most important is that we have accurate results, even if that takes a little longer.”

Mail-in ballots have to be postmarked by today to count, but that has been challenged in the Supreme Court.

“Everyone should have patience. While we expect the overwhelming majority of Pennsylvania ballots to be counted in a few days, our first priority and our county’s first priority is to accurately and securely count every legal ballot cast and then to count them as quickly as humanly possible,” Pennsylvania Secretary of State Kathy Boockvar said.

Boockvar is pushing patience. She says the results are normally just predictions and are never final on Election night, something she says will certainly hold true tonight.

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Alexandria Hoff