Principal Eileen Reiter wishes she could give all of her best teachers the raises she thinks they deserve.

That’s not possible under New York City’s traditional teacher pay system, which is based on experience and education credits. But Reiter’s school, P.S. 112 in East Harlem, did become eligible this summer to boost pay for some teachers by $7,500 as part of a program created by the new city teachers union contract.

Reiter said it’s a good start, but not enough for her school, where all teachers were rated “effective” or better on last year’s evaluations and six teachers applied for three available “model teacher” spots.

“I have so many teachers who could have been model teachers,” said Reiter, who added that it has been challenging to describe the compensation change at her school. “The way I explained it to the staff is that it’s not an award. It’s a lot of extra work. And it’s just for one year.”

P.S. 112 has had more leeway than most, as one of just 24 schools eligible to give the raises to teachers when the school year began. The limited rollout of the paid leadership positions, to less than 2 percent of the school system, initially, is emblematic of how cautious the city is being in implementing a new pay model that departs significantly from the way city teachers have been paid for decades.

When the city and the United Federation of Teachers first announced that three different leadership positions had been created by their contract agreement in May, officials said they would serve as tools to keep top teachers in the classroom by offering bonuses of between $7,500 and $20,000 for work teachers were already largely doing for free.

“How do we make sure that these schools, and people who are doing extraordinary work, are also given some compensation for the work that they’re doing?” Chancellor Carmen Fariña said then.

The program is set to expand over the next few weeks. Earlier this month, the city opened up the applications for two of the positions to teachers in another 175 schools, many of which are already taking part in other new education initiatives like the Learning Partners program and PROSE schools. Also eligible are schools in East Harlem’s District 4 and Brooklyn’s District 23, which officials said were chosen for their concentrations of high-need students and interested superintendents. Race to the Top grant money is simultaneously being used to fund the leadership positions in a small group of Bronx high schools, officials said.

So far, officials said they have received 500 applications from 150 schools, although some teachers applied for more than one job.

All three of the new positions offer more pay for specific additional responsibilities and additional time on the job. Those responsibilities are the major difference between New York’s changes and compensation systems established in recent years in other cities, such as Cleveland, Baltimore, and Washington, D.C., where teacher bonuses have been tied directly to performance evaluations or based on student test scores.

For example, the city’s new “model teacher” position requires teachers to use their classrooms to demonstrate lessons and new teaching techniques. They will work an extra two days during the summer and two hours a month during the school year, and be freed from teaching some number of periods each week for that work.

The “ambassador” teacher position, which won’t be offered this year, requires teachers to leave their school for a year and work elsewhere in the same borough in addition to doing extra work during the school year and summer. “Master” teachers, who receive a $20,000 salary increase, will continue to teach in their schools but will be expected to coordinate teacher training, coach other teachers, and serve as a leader on “school teacher teams.”

Academy for Careers in Television and Film Principal Edgar Rodriguez said getting money to promote top teachers at the a small high school in Queens was “a great way to legitimize” jobs that he had been delegating since he took over nearly two years ago.

“Whether or not the roles formally existed, I had a number of teachers who were leaders,” he said.

But the promotions haven’t been universally embraced. After being notified that they were eligible earlier this month, entire staffs at least two schools agreed that they wouldn’t apply.

“This is a highly collaborative and democratic staff and it would be detrimental to our staff culture to elevate a small number of people when everyone is participating,” said Julie Zuckerman, principal of P.S. 513 in Washington Heights. P.S. 321 in Park Slope also declined to participate, Principal Elizabeth Phillips said.

Teachers at some eligible schools argued that pay bumps for one or two teachers aren’t the best way to spend money, since the city has only offered to pick up the tab for the bonuses this year. Rosie Frascella, a teacher at International High School at Prospect Heights, said she did not plan to apply for the model or master teacher positions.

“In my school right now, there’s not a lot of money for after-school programs, and it’s kind of a waste of money to give one teacher an extra $20,000 to be a master teacher,” said Frascella.

In some ways, the new positions are an expansion of similar programs that have been scattered across city schools for years. There is already a federally-funded career ladder program in its second year at 75 middle schools, while the city’s “lead teachers” program extends to 250 teachers in 170 schools who earn an extra $10,000 each to do much of the same work that the new “model teachers” will do.

Supporters of alternative compensation systems say New York City’s contract doesn’t go far enough. To qualify for the raises, teachers need to be rated “effective” or “highly effective,” which TNTP President Tim Daly criticized as too low a bar.

“In the big picture, the contract reflects, from a compensation perspective, a commitment to the existing system,” Daly said.

Union officials say they are betting that the rewards for doing specific extra work won’t damage their long-held position that teacher pay shouldn’t be tied to measures of teacher quality. They also said a careful rollout would ensure the program is successful.

“If it’s done right in an equitable fashion, we have the ability to build capacity within our ranks,” said UFT Vice President Karen Alford, who served on the union’s negotiating committee. “It’s about making sure that people who are clearly leaders within our schools are recognized.”