The Surface Transportation Board (STB or Board) is adopting a final rule to define "on time" and specify the formula for calculating "on-time performance" for purposes of Section 213 of the Passenger Rail Investment and Improvement Act of 2008. The Board will use these regulations only for the purpose of determining whether the "less than 80 percent" threshold that Congress set for bringing an on-time performance complaint has been met. In light of comments received on the Board's notice of proposed rulemaking issued on December 28, 2015, the proposed rule has been modified to deem a train's arrival at, or departure from, a given station "on time" if it occurs no later than 15 minutes after its scheduled time and to adopt an "all-stations" calculation of "on-time performance."