On September 25, the Surface Transportation Board (STB) announced that Vice Chairman Daniel R. Elliott III, a Democrat, will leave the Board as of September 30. Elliott, who is approximately halfway into his second five-year term, previously served as STB chairman in the Obama administration.

Elliott’s departure will shrink the five-member Board to just two members: Acting Chairman Ann Begeman, a Republican, and Deb Miller, a Democrat whose first five-year term expires on December 31, 2017, although she may serve for up to one additional year until she either is renominated or replaced.

Congress expanded the STB from three to five members in December 2015, but the two added seats were never filled under the Obama administration. Since his election in 2016, President Trump has not announced any STB appointments. Thus, Elliott’s departure will create a third vacancy, with the potential for a fourth vacancy at the end of 2018, which could leave the STB with just one member. The three vacant seats must be filled by one Democrat and two Republicans.

Due in part to the current two vacant seats, the agency already had suspended activity on several major rulemaking proceedings that have the potential to alter the rail regulation landscape. With a third vacancy looming, the prospects for advancing those proceedings anytime soon appear to have decreased. To help ensure that the STB can continue its important work, interested parties should communicate to the Trump administration the importance of filling the vacant seats.