SANTA CLARA — A giant countdown clock ticks down by the hundredth of a second in the nerve center of the San Francisco 49ers new stadium like the scoreboard at an NFL game.

It’s a constant reminder for workers that they are quickly marching toward the end zone to finish pro football’s newest stadium by next summer.

They’re more than halfway done and two weeks ahead of schedule, with the clock now counting down to the end of June. That’s more than a month before the preseason starts, leaving time for concerts or other events to be scheduled before the 49ers start to play.

“We, of course, have a year to go, and things happen,” said Kavinder Singh, vice president for the lead builder, Turner Construction. But the firm’s track record so far leads him to believe it can keep up the pace. “The difference is palpable. (The stadium) transforms itself on a regular basis.”

Workers in Santa Clara devoted 2012 to installing the towering concrete and steel shell of the stadium, spending about $26 million a month. They have been even busier this year working on the inside, burning through an average of $37 million each month.

The seats, scoreboard and even the playing field will start going in during the next few months, and the interior — from the concession stands to the bathrooms to the locker rooms — is already taking shape.

“It’s just amazing,” said Sylvano Simone, who notices something new about the stadium every day he drives by on his way to his tennis academy across the street. “They’ve just been pretty methodical about it. You keep seeing it getting bigger and bigger.”

While Colin Kaepernick and Patrick Willis run sprints at the adjacent practice field preparing for the team’s 43rd and final season at Candlestick Park, the focus at the construction site is already on next year.

A miniature city is taking shape, with “superhighway” concourses ringing the outside of the stadium for fans to get in, get out and meet up with friends. On the inside, they’ve started building concession stands pre-loaded with beer taps and Pepsi machines, and 42-inch monitors fill in 60-foot-wide “neighborhood” spots for fans to hang out.

Visitors can now ride the escalators and elevators up 230 feet to a rooftop garden, where fans next year will be able to grab a beer and soak in the view from the bay to the Santa Cruz Mountains.

At the future 50-yard line, the four 500-ton cranes that lifted massive steel beams into place for months are gone and the trucks that have moved around the dirt field like X’s and O’s on Jim Harbaugh’s clipboard will soon depart so the sod field can be planted in December. In six weeks, workers will install seats along the rows of concrete, and in a few months, they’ll slide a 192-foot wide Daktronics TV into the giant scoreboard frame hanging over the field.

Even some of the finishing touches have arrived, from fabric and paint samples (lots of red and gold) to splash tiles to player lockers.

Hotels and restaurants are already preparing for the grand opening. David Ebrahimi, owner of David’s Restaurant across the street, said he’s installing TVs for a sports bar feel and plans to open a postgame nightclub at his eatery.

“It’s going to go really fast” until it opens, Ebrahimi said.

A big reason work has gone so fast is that many of the stadium’s features are being manufactured off-site and shipped to Santa Clara, project co-director Robert Rayborn said. By the time the seats arrive, workers merely need to “open the box, slap it on the rail, tighten two bolts, and they’re in.”

For the heavy lifting, crews use a new 3-D mapping system to detect design problems before they happen — like a vertical steel beam crossing the path of a horizontal pipe. And the dry winter saved plenty of headaches.

In all, since planning began in 2006, Santa Clara officials and the 49ers have spent $556.6 million on the $1.3 billion project, which is now considered 56 percent complete in terms of time and budget. Since the April 2012 groundbreaking, Turner and Milpitas-based Devcon Construction have maintained a spending pace of $1 million a day. In all, 5,000 people have worked on the site for a combined 1.5 million hours.

But the project has had its problems, most notably in June when veteran worker Donald White, who was 63, was killed after being hit by a counterweight while inside an elevator shaft. Work stopped for two days, and state workplace safety officials are expected to continue investigating through the end of the year.

Rayborn said many of the blue-collar workers and managers around the stadium still aren’t comfortable talking about it and avoid the topic while on the job. Still, pictures of White are scattered around the site, and counselors have been called in to talk with grieving workers.

Singh said it’s tough to understand why White was in the elevator shaft, something he would have learned to avoid early on during training. No changes have been made to the construction process and safety standards since the fatality, Singh said, adding that “we’ve moved on.”

“None of us ever want to have something like that happen again,” Rayborn said.

That means going back to work, for the next 317 days, 23 hours, 28 minutes and a few seconds, as the countdown clock showed last Friday morning.

Rayborn said he “can see a little bit quicker step in” the workers with football season starting and the finish line now in sight.

“We can be 11 months or even 10 months from the first event,” said Erich Smith, who commutes past the stadium every day to his job as general manager of the Hilton Santa Clara next to the project. “All of us are somewhat amazed at just how fast it has gone up.”

Contact Mike Rosenberg at 408-920-5705. Follow him at Twitter.com/rosenbergmerc.