The 175,000 U.S. workers who are on four-day-week schedules will go back to Monday through Friday duty very shortly, unless Congress pumps life into the program allowing some feds toput in long days to earn long weekends.

In addition to the four-day-week people, some, but not all, of the 300,000-plus feds who are working various other forms of flexitime that occasionally exceed eight-hour days or 40-hour weeks could be returned to the traditional eight-hour day next month unless PL 95-390 is extended or replaced. PL 95-390 is the three-year-old law that encouraged agencies to experiment with flexible schedules, and made the four-day week possible by allowing folks to voluntarily waive overtime for work in excess of eight hours per day.

Fate of the program depends on a compromise between the administration and Rep. Geraldine Ferraro (D-N.Y.). Ferraro wants the program extended, as is, by law. Reagan's people say they like the four-day week and flexitime concept, but want management to have complete control over its application, who's in and who's out.

Sen. Ted Stevens (R-Alaska) this week plans to introduce a compromise bill that he hopes will satisfy both sides and keep the program (due to expire March 29) going.

If the legislation dies, everybody working four-day-week schedules, and most people on compressed or expanded workdays covered by PL 95-390 will have to return to the eight-hour day, five-day week. Office of Personnel Management is advising agencies whose payroll period ends this weekend to wind down four-day-week programs unless Congress gives the clear sign it will extend the program.

Federal officials say that most workers whose flexible schedules are authorized by Title 5 of the U.S. Code (which permits agency heads to vary work hours provided no overtime is incurred) can remain on their schedules even if the law expires, provided their agencies decide to keep the program. In addition, programs (except those allowing people to work more than eight hours a day) set by union contract would be continued at least until the current contract expired.

This is the situation as of today: Something's got to give by March 29. If the program is continued, work programs will be maintained subject to any new changes enacted into law.

If the program dies, everybody on the four-day week and everybody now putting in more than eight hours a day without overtime will be moved back to the regular eight-hour day, 40-hour week. Persons working flexitime schedules that do not require more than eight-hours-per-day work may remain on them if their agencies stick with the program or if their plans are part of union contract.

You should know by early next week whether the program will be continued, and, if so, in what form. Otherwise, you may have to make some adjustments in your current car pool and get ready to rejoin rush hour.