This time of year, the U.S. Postal Service sorting facility in Scarborough is open 24 hours a day, seven days a week. The facility has nearly 500 employees, and in the last few days before Christmas, 120,000 to 130,000 items will pass through each night. Marianne Parker has worked as a mail handler for 27 years. The most difficult part is “really watching out for people when you’re on a piece of equipment,” she said. “You’ve got to be mindful.” The most interesting part is the people, Parker said, “because we have such a diversified group of young people, middle-aged people and seniors. So it’s really interesting to get to know … where people are from and what they’ve done before they came here.”