While Congress and the White House talk of a miracle cure soon, some of the 50,000-plus federal workers facing painful grade and pay cuts are quietly being measured for - or lowered into - bureaucratic coffins by their own agencies.

The workers - many with 20 or more years service - are threatened with demolition either because of Carter inspired reorganization of their agencies, or a new government drive to eliminate improper inflation of civil service pay and grade levels.

Although nobody knows how many government workers are being paid too much - or not enough - for the work they do, offical estimates indicate from 50,000 to 115,000 employees may be overgraded because of past misclassification of their job duties and skills. That is a multimillion dollar (if not billion dollar) item.

In addition to the new attention being paid to old classification mistakes, many younger, lower-grade and otherwise less vulnerable federal workers could get the ax if reorganization leads to grade shakeups and layoffs.

The President has promised (over-promised in the view of many of his top-advisers) that nobody in government will be hurt by reorganization. Presumably that means nobody will be fired, cut in grade or salary.

Congress - at least the House Post Office - Civil Service Committee - has promised that no civil servant should have to suffer because somebody discovers 10 years after the fact that his (or her) grade was misclassified.

In effect the White House doesn't care about protecting anybody from grade cuts because of old classifaction errors and the Congress doesn't care about protecting anybody because President Carter made some rather tall promises trying to sell his reorganization to the bureaucracy.In reality, both groups will probably agree to a compromise when legislation surfaces - next February or March - to protect employees from the ravages of both misclassification and reorganization.

In the meantime, workers are living on promises and (however well-meaning) sweet talk from Pennsylvania avenue and Capitol Hill. Their agencies, under the gun from the Civil Service Commission, are pushing demotion actions with varying degrees of enthusiasm. Ultimately, the frontline troops take it in the neck for the mistakes, or the unkept or delayed promises.

CSC has permitted Health, Education and Welfare to forget about down-gradings for the foreseeable future, because HEW faces big reorganization problems.Also because Secretary Joe Califano knows how to yell loud, and how to pull levers in the bureaucracy.

Other agencies aren't being so lucky. While their employees read and hear about the progress of no-fault job protection bills, their agencies are being told by CSC to get their grade levels in order. Some are delighted to whack GS 14s back to GS 12s. Others have been fighting with CSC, bargaining or delaying the demolitions which are supposed to take effect within eight pay (for 16 weeks) periods after the classification error is found and confirmed.

A top aide at the White House said "reorganization hasn't made much of an impact yet" in agencies but when it does the President expects agencies to "deliver" on his nobody-gets-hurt order, whether there is legislation or not. Publicly, agency heads snap to attention, but in private, personnel officials say there is no way they can handle major reorganization without legal authority of preserve and protect jobs.

From Capitol Hill, the Post Office Civil Service Committee has let it be known that Chairman Robert Nix (D-Pa.) expects his no-fault-demotion bill will be law early next year. Also that Nix believes it would be a "mistake" for agencies to push demotions because of job classification errors. If it comes to that, the Nix bill would make things right since it calls for grade-saving actions for anybody demoted within a two-year period prior to the date the bill becomes law.

So while the White House and Congress talk about demotion protection, and nobody being hurt, agencies are sending out notices to employees telling them to get used to a new (lower) grade at least until one of the long-promised legislative miracle drugs comes along.

Auto Allowance: The government has incresed the mileage allowance for employees who use their own cars on official business. The increase from 15.5 to 17 cents per mile officially took effect yesterday (Sunday).

The mileage increase will also affect thousands of salesmen (and women), inspectors, auditors and other nonfederal employees who drive for their employers if their company or union follows the federal practice. Many firms base their rates on what the government gives its travelers. And that, as of today, is 17 cents a mile.