Kristen Anderson-Lopez, who cowrote the songs for the Oscar winner Frozen will make her Broadway debut with In Transit, opening Dec. 11. This a cappella musical, co-penned with James-Allen Ford, Russ Kaplan, and Sara Wordsworth, follows a group of ambitious New Yorkers through the subway.

In Transit had its first workshop in 2008 at the Eugene O’Neill Theater Center, then appeared Off-Broadway in 2010. How has it changed along the way?
Actually, it has been in transit since 1999 when I wrote the first song. It all started with a group of friends and I who were in an a cappella group together, and a few of the songs that we had written are still in the show. It has evolved many times since then as we became older and better storytellers. Between the Off-Broadway and the Broadway version, we have added several components. We added another 4 voices; the Off-Broadway show had 7 voices, and now there are 11. We also added Deke Sharon, cappella guru behind “The Sing-Off” and the Pitch Perfect movies–he sort of created the American a cappella sound and movement almost singlehandedly, and he has done all the arrangements for this 11-part version. We have added Kathleen Marshall, three-time Tony Award-winning director, who is just an incredible mind for matrices and has got this ability to imagine the 11 components in space and know where they all will be. It really is a complicated show–the cast, the stage. You need to have one of those minds that can keep several things tracking at the exact same time.

Do you think that the popularity of Pitch Perfect and “The Sing-Off” helped bring In Transit to this point?
It certainly didn’t hurt. When we started this a lot of people didn’t know what a cappella was. For advertising in the Off-Broadway version, we called it “vocal orchestration,” because a cappella was this weird Latin term that the marketing team was afraid would alienate people. Now our tagline is “Broadway’s first a cappella musical.” The culture’s awareness and understanding of a cappella, and all the things a cappella can do, has changed. It’s not just a bunch of old guys singing “Blue skies smilin’ at me!”

There is also some beat-boxing in the mix.
At the heart of our show is a beat-boxer, and In Transit might be one of the first shows to celebrate this whole talent. There is a whole group of people that are like human drum machines, and they all have these incredibly specific virtuosic talents. We are really excited to put that on the Broadway stage, too.

What is your collaboration process with your other cowriters?
It is a really unique process and everyone who has worked with us is always amazed at how we are a democracy. We have a democratic writer’s room model, and we are really good friends. When I was lonely and lost in my late 20s, I found them and we became each other’s tribe. These were my people. We have a shorthand, because we have so many years of laughter and life under our belts. It’s very “best idea wins, best joke wins.” The boys tend to be the composers, and the girls tend to be the lyricists, but there is overlap in that. We all write the book together; one of us will draft a scene and then we will polish it together. It is all very non-ego.

So why a musical on the subway?
The show is a love letter to New York and the people who make up New York. I think the one thing that connects the majority of the population in New York is that we are all trying to get somewhere, whether it is in our careers, our love life, financially. Everybody is a motivated person trying to get somewhere, and life has a way of getting in the way of where you want to get. We thought the MTA was the perfect metaphor for the obstacles that slow you down, cause delays, and sometimes make you stuck.

Any terrible subway experiences you can share?
I did, and luckily we were above ground. When I lived in Astoria, which has an elevated track, I got stuck and held on the subway for close to 90 minutes. There was a pregnant woman on the train. They made us get off and we had to walk on the upper level, 100 yards or something, to the next station. What is kind of amazing about New Yorkers is that in those moments, when the chips are down, New Yorkers take care of each other. Everyone was taking care of this pregnant woman.

What’s your advice to young NYC artists who are still in their ramen days?
Find a community. It is the most important thing. The BMI Lehman Engel Musical Theatre Workshop saved me: I found my best friends, my husband, and my career through there. Not everybody is a musical theatre writer, so for some people finding a community is through a class, a church, a workplace activity.

We did not have social media when I was my 20s, but now I find that it gives me the false perception that I am connecting with people. That is something I see my millennial pals struggling with: how easy it is to feel like you’re connected, but you’re not. You’re eating your ramen in your apartment streaming Netflix and you should be out having those game nights and walks by the river that make living in New York something extraordinary.

I could definitely use more game nights and walks by the river.
Couldn’t we all!

Besides long walks by the river, do you have any guilty pleasures?
Diet Peach Snapple. I also really love trolling real estate websites for places out in the country. My husband calls it my real estate porn.

Any plans to move?
Not really—we don’t have time. I love to dream about it. And when it finally happens, I will be really well informed.

What is always in your fridge?
Moldy grapes. We always buy grapes and then we don’t eat enough of them and then they get moldy.

What is one thing that you always have with you when you work?
Ink on my hands. I don’t know how people write without getting ink on their hands. If I’ve been writing for a long time, I look like Jackson Pollock has taken a ballpoint and gone at me.

What do you sing in the shower?
I write new lyrics in the shower. This morning I was mulling on a lyric. I used to sing in the shower before I had to write the songs, and now I scribble orally in the shower—that sounds dirtier than it should. But I try things out in the shower, how a hook sounds or a melody.

What three things would you take with you to a desert island?
Water. My biggest thing is hydration, I can’t drink enough water. My family. And sunscreen. That is such a mother answer.

So do your kids still want to watch Frozen or are they tired of it?
They were the first people, so they were like when an indie group becomes popular and you’re the first people who discovered them and then everybody else discovers them. They were like, “Ugh, that was ours and we don’t care anymore.” They were anti-Frozen for a while, but they still sing it. We did a concert this summer at the O’Neill [Theatre Center], and they sang “Do You Want to Build a Snowman?” together.

Your next stop on the Broadway train will be Frozen the Musical. How are you changing the movie for the stage and juggling both these projects?
Frozen Broadway was actually a year of very hard labor. We took 8 songs—what the movie has—and turned it into 23. We’re proud of it and I am excited to share it with the world because we got to go much deeper into things, and the relationship with Anna and Kristoff. It was really fun to spend some time writing their chemistry. We did a lot of looking at yoiking.

Say what?
The Norwegian Sámi people, an indigenous group of people—they have this thing called yoiking, which means “to make present.” It is a kind of singing and yodeling—it is unlike anything you’ve ever heard. We got to dive into that and put more of that into the score.