Jammed.

Stressed.

Challenged.

No, not SEPTA.

Verizon, AT&T, T-Mobile, Comcast and Philadelphia officials are holding their breath as millions of Eagles fans converge on the Philadelphia parade route on Thursday with their smartphones. What will happen when they try to connect on FaceTime? Or upload, en masse, photos and videos?

"The telcos and the city worked together quickly to boost capacity along the route," Philadelphia spokesman Mike Dunn said in an email. But he added, "While providers have boosted capacity, parade-goers should expect service to be challenged."

Companies have put tens of millions of dollars into boosting the city's wireless capacity for the Pope Francis visit, the Democratic National Convention, and the National Football League draft. But celebratory Eagles fans will place huge and unpredictable demands on the city's cellular and WiFi networks along the parade's five-mile route from the South Philadelphia sports complex to the Art Museum. Telecom companies have concentrated much of the wireless upgrades on the Benjamin Franklin Parkway — the site of the NFL Draft and the Welcome America concerts.

Responding to the city's call for more wireless for the Eagles parade, Verizon Communications Inc. has parked a mobile cellular site at Marconi Plaza, in South Philadelphia. "We're prepared," Verizon spokesman David Weissmann said.

Verizon considered the parade an "all hands on deck" day and that network managers would be adjusting to the capacity demands as the Eagles make their way to the Parkway, Weissmann said.

T-Mobile director Kerri Strike-Stahller said that "Philadelphia officials contacted us last Wednesday to start preparing for this" and that she was confident in the company's network. T-Mobile has invested significantly to upgrade its Philadelphia network and it has boosted capacity for the Eagles parade with a mobile cell site around City Hall, she said.

Strike-Stahller — who said she will attend the parade — suggested that data-hogging parade videos be shared later with friends and family members, "so we can all enjoy the network."

AT&T expanded its 4G capacity in Philadelphia by 35 percent in 2017, spokeswoman Brandy Bell-Truskey said. "We feel confident that fans will be able to share those once-in-a-lifetime moments from the parade through texts, tweets and selfies," she said.

Comcast, which has been gingerly entering the wireless business, won't open its extensive WiFi network to the public along the parade route because it likely doesn't have the capacity for the crowds. "While Xfinity continues to expand our WiFi network – we have more than 14,000 access points across Philadelphia – it's difficult to predict the impact this kind of data use may have in such a concentrated area," the company said on Wednesday.

One suggestion for Eagles fans who are Comcast cable customers: Find a WiFi hot spot a block or two away from the parade route and upload photos or videos there away from the crowd. Comcast has many spots along South Broad, according to its WiFi map. There are fewer along the Benjamin Franklin Parkway, but more a block or so east.