double-back
v.— «“I think the antiquated system we have had of ‘doubling back’ should have been replaced long ago.”…The former double-back arrangement meant that every other day, an officer who finishes an eight-hour shift at 8 a.m. goes back to work at 4 p.m. for eight more hours.…Gone will be the old double-back system for the night platoon, which meant working 16 out of 24 hours every other day. With court appearances and second jobs, sleep became rare for some officers.» —“New Pact Should Result In Better Police Morale Tiring ‘Double-Back’ System Removed” by Michael Beebe Buffalo News (New York) Apr. 23, 1993. (source: Double-Tongued Dictionary)