The second set of tracks was considerably smaller than the first.

There's a single set of tracks coming from a distance away.

They'd left a set of tracks any idiot could follow.

There was just one set of tracks, and they were his.

"I saw more than one set of tracks in the mud back there."

Often, there is more than one set of tracks on the railway line.

You can only do that by laying a new set of tracks.

She pointed to the one set of tracks leading away.

She continued toward the back, and came to a halt at another set of tracks.

Just keep the set of blue tracks on your left.