MARC EBUÑA, the co-founder and president of TransitMatters, is leaving the transportation advocacy group to take what he described as an entry level job at Keolis Commuter Services, which operates commuter rail for the MBTA.

Ebuña, who disclosed his departure while asking a question at a forum on commuter rail Wednesday night, said he starts his job as a passenger information center specialist on Monday.

TransitMatters has become an influential transportation advocacy group in Massachusetts over the past couple of years. Most of the members are millennials. What sets them apart from other transportation advocates is that they make their case using analysis, logic, and data – usually the MBTA’s own data.

“This loose confederation of self-described nerds, launched initially in 2009, has become almost a shadow transit agency,” CommonWealth reported in its October 2017 issue, which featured a picture of Ebuña and two of his colleagues on the cover. “They don’t just advocate for pet projects and policies; they actually roll up their sleeves and dig into the data. That’s what sets them apart; they know what they’re talking about.”

From left, Andy Monat, Marc Ebuña, and Ari Ofsevit of TransitMatters.

TransitMatters convinced the T to scrap a $1.3 million design of a new Auburndale commuter rail station, saying the plan would hinder the operation of the Worcester line. It also convinced the transit agency to change the way it shuts down at night and to launch an all-night bus service pilot. Earlier this year it released a report calling for transforming the commuter rail into a system of regional rail.

Politico ran a lengthy profile of TransitMatters in late October entitled: “They’re Bold and Fresh: The Millennials Disrupting Boston’s Transit System.”

Joseph Aiello, the chairman of the T’s Fiscal and Management Control Board, has lauded TransitMatters in the past. “They are an organization composed of very, very smart people,” he said. “I’m delighted that they’re incredibly public spirited and that they dive into very, very specific technical matters and supplement the good work the T does on a regular basis. I hope they keep at it. We’re a better T because of them.”

TransitMatters has been an all-volunteer organization, but that may be changing. The group recently announced it is looking to hire its first employee – a chief operations officer/development director. The job description says the COO would work with the board to brainstorm and implement a two-year development and strategic plan.

Ebuña said he will miss TransitMatters, but felt the job with Keolis will allow him to transition professionally from information technology to transportation. He said the experience he gains with Keolis will allow him to see how a transportation agency works from inside.

“That’s important, having that practical knowledge and experience under my belt so that people take me seriously when I say things and I’m not just talking out of my ass, so to speak,” he said.

TransitMatters participates monthly on CommonWealth’s Codcast, hosting guests for chats about transportation issues.