Indian File

Indian file is a method of marching whereby the troops follow one-nehind the other, each stepping in the footsteps of the man in front, and the last man obliterating the footsteps. The method was used by American Indians to disguise both the route taken and the number of soldiers in the column.
Found on http://www.probertencyclopaedia.com/browse/FI.HTM

Indian File

Single file.
Found on http://www.xmission.com/~drudy/amm/gloss.html

INDIAN FILE

When a field of horses race in single file, one behind the other.
Found on http://www.encyclo.co.uk/local/21679
No exact match found