Now, perhaps the most important point: The residency was free. According to Gross, all Amtrak asked was that she send out a few tweets while she was traveling, and do an interview for the company's blog at the end of her trip.

All told, it sounds like a truly exquisite experience. Gross later detailed her trip in The Paris Review: "I’m only here for the journey. Soon after I get to Chicago, I’ll board a train and come right back to New York: thirty-nine hours in transit—forty-four, with delays. And I’m here to write."

What, exactly, is the appeal of writing on a train? In a phone interview with The Wire, Gross described the train ride as a "unique environment for creative thought," one that "takes you out of normal life." She won't find much disagreement. Now more writers (The Wire's staff included) are clamoring for their own Amtrak residency.

“I’ve seen a billion tweets from other writers saying ‘I want one of these’,” Gross said, probably being a tad hyperbolic, but it's true that once Amtrak actually does start offering writers' residencies regularly, they're going to be very popular. Julia Quinn, social media director for Amtrak, tells The Wire that there has been "overwhelming demand" from people interested in the program – part of the reason the company is intent on turning this into a regular operation.

Though Gross' residency was a so-called "test run," Chee, the man who started this whole thing, tweeted Wednesday that he had set up his own.

I can announce my @Amtrak writer's residency dream came true, thanks to them-- am set for a trip from NYC-Portland, OR in mid-May. — Alexander Chee (@alexanderchee) February 19, 2014

So this is really becoming a thing, and we could not be more excited. But there were still a few questions that needed clarifying before we threw a celebration, so we got Quinn on the phone to discuss the program in further detail. Let's break it down:

1. What will a long-term residency program look like?

A lot is still up in the air with regards to a future program. Quinn described it as "an idea dreamed up by Amtrak fans and customers," and a lot of the details still need hashing out. "We would’ve never known until really in the last 48 hours what type of response a program like this would warrant, and we have been pleasantly surprised," Quinn said, so the outline being formulated is very new. But the goal, eventually, is to "engage with writers several times a month." There may be a "tiered approach," though the specifics aren't fully worked out, with the focus on individuals with a strong social media presence.

2. How much, if anything, will an "Amtrak residency" cost?

Gross's residency was free, and Quinn confirmed that the plan is to keep the program if not free, then fairly low-cost. But Quinn points out that the residency was "free to Jessica, not free to Amtrak." When Amtrak begins offering this program on a regular basis, Quinn said "we need to weigh [whether] it’s a good investment on our end” – because Amtrak can't just start giving away free rides willy-nilly. (Especially not when it has a significant amount of debt). It's about building a "mutually beneficial relationship" with writers, according to Quinn, and ensuring that a long-term program is sustainable. For now though, the program looks to remain free, if limited.