As far as I've seen, it only has one save, and it's only the last thing you were doing. Pressing continue will start you where you left off last session.
I keep losing progress on cities from Career mode. Finished normal career and kept playing washington, I go back and its at zero now.
Same here, didn't played for some weeks, just wanted to continue playing today and my Savegame is back to zero. Also the stuff from the DLC seems to be not be there anymore.
Each map only has one save each which auto saves at the end of each shift. Be sure not to hit reset by accident. You can manually backup saves (BUT shouldn't need to) by going to: C:\Users\username\AppData\LocalLow\JutsuGames\911 Operator The save files for each map are in the Career and FreeGames folders - note that if you played Chicago in Career you're progress does not transfer to Free Play. Your map unlock progress is held in PlayProfile.xml
You can manually backup saves (BUT shouldn't need to) by going to: C:\Users\username\AppData\LocalLow\JutsuGames\911 Operator
The save files for each map are in the Career and FreeGames folders - note that if you played Chicago in Career you're progress does not transfer to Free Play. Your map unlock progress is held in PlayProfile.xml