In the photos and video coverage of the 142nd Kentucky Derby yesterday, you might’ve noticed a line of Navy sailors standing along the rail.

They’re from the Navy Operational Support Center on Southside Drive in Louisville. And they were at Churchill Downs for both Oaks and Derby “manning the rails” along the finish line.

The tradition comes from sailors who were pulling into port. They’d get into dress white or blue uniforms and stand along the flight deck as their ship arrived. The pose itself is similar to standing at attention, but they hold their hands behind their back.

Churchill Downs invited the sailors to man the rails this year, they told us, and they appreciated the gesture. It was the first Derby for Charlie Cox, a Louisville native who’s been in the Navy for 17 years and just transferred back from San Diego.

“We’re honored to be able to be a part of it and help support our community and represent the Navy,” Cox told us.

Listen to Cox and his fellow members of the Navy describe their experience at the track in the audio player above.