Shani Moser is a teacher without a classroom at Madison High School in Vienna. The Spanish teacher pushes a cart with her items used in class. (Astrid Riecken/The Washington Post)

Students bustling in the hallways of Fairfax County’s James Madison High School hear Spanish teacher Shani Moser before they see her: The handcart she rolls from class to class is decorated for the holidays with bells.

Moser no longer has a classroom to call her own. Instead, she carries all her materials with her as she shuttles throughout the school to meet her students in rooms borrowed for the class period from other teachers.

A surge in enrollment in Fairfax has forced Moser and scores of other teachers to travel from classroom to classroom. Since 2006, the school system has grown by more than 20,000 students, or almost the entire enrollment of Arlington County public schools.

Many schools are packed to and beyond capacity, and officials say there’s no relief in sight. The Fairfax County School Board must address a projected $130 million deficit next year, partly driven by $25 million in costs associated with rocketing student growth.

At the same time, the administration has not been able to build enough new schools to accommodate its students.

Beth McConnell, a Mount Vernon Woods elementary art teacher, said she had a classroom last year but was alerted over the summer that she would be moving to a cart, joining a Chinese teacher, a music instructor and another art specialist.

“It made us all feel like we were not important,” said McConnell, who visits up to five classrooms a day. “Most people on carts don’t feel appreciated.”

It’s not clear how many teachers work from the carts. Some teachers who use them say it can be a challenge to ferry around all the books, papers and props they need for lessons. And without a dedicated classroom, they say, it can be harder to find a quiet space to meet with students or parents and to grade papers.

Steven Greenburg, president of the Fairfax County Federation of Teachers, says students face a lower-quality education when teachers use carts. And it’s a trend he says could continue.

“I think that for the best young teachers, it’s not going to be very attractive to them to come work where they don’t have their space,” Greenburg said. “It hurts our ability to hire people if they don’t have that professional courtesy.”

Kimberly Adams, president of the Fairfax Education Association teacher organization, said that many teachers now work in hallways or old broom closets converted into class space. Having teachers work from carts is another symptom of crowded schools, she said.

“Teachers are working pretty hard to get their job done in not- so-adequate conditions,” Adams said. “Fairfax can do better.”

Kelly Andrews, a part-time Washington Mill music teacher, said she worked in a trailer before moving to a cart. With her school overcrowded, Andrews says she doesn’t expect to get her own classroom anytime soon.

Andrews said that being on a cart is “part of being a team player” but that, in the end, it’s her students who suffer.

For example, Andrews said, she cannot load glockenspiels and xylophones onto her cart to teach the students percussive rhythm and melodies.

And she said she loses instructional time rearranging desks in the classrooms she visits when she needs room to lead students in dance movements to help illustrate a musical idea.

“It makes me feel bad, because being on a cart, I cannot do as much as when I had my own space,” Andrews said. “It brings me down that I can’t be the best that I know I am because of a situation I cannot control.”

But being on a cart is not an inconvenience for all teachers. Luanne Inn, a Woodley Hills art teacher, said she accepted her position knowing that she’d have to wander.

“What I find is that a skilled teacher can teach in any situation,” Inn said. “Regardless of the space, I can make it work.”

Moser, the Spanish teacher, said she has made the best of the situation by decking out her cart for the winter holidays with Christmas lights, a stocking and reindeer antlers. With limited space, she said, she’s become more organized. Moser said she also teaches the students how to be more responsible for their own materials.

“You have to be very well planned for everything,” Moser said. “I cannot be a walking filing cabinet. I have no room for extra copies.”

Because she’s always out and about, however, students sometimes struggle to find her if they need help. Moser said that because she’s rarely in the same place for long, it has sometimes taken students months to track her down in Madison’s maze of hallways.