Christine Clark has worked more than 30 years for companies with pension plans for their employes. Despite her lengthy career, she has no expectation of receiving a single penny in private retirement benefits.

Clark and more than 10 million other American workers like her are the losers in what one expert characterizes as the pari-mutuel system of American pension plans -- a system where many pay and relatively few collect.

That is not exactly what President Gerald R. Ford was predicting on Labor Day 1974 when he hailed a new pension bill as a landmark.

"This legislation," Ford said as he signed the Employment Retirement Income Security Act (ERISA) into law, "will alleviate the fears and anxieties of people who are on the production lines or in the mines or elsewhere, in that they now know that their investment in private pension funds will be better protected, they have a vested right."

In fact, ERISA apparently has fulfilled that promise for workers who qualify for pensions. It has not assured protection for many American workers who choose to or are forced to change their jobs every few years, and it has provided only limited protection for workers whose companies leave them -- either by picking up stakes or going under. Nor has it helped the millions of workers whose employers do not offer pension plans or profit-sharing as part of their compensation.

That in turn means that Social Security, despite the growing demand to ease its burdens, probably will have to continue as the pension system of last resort for millions of Americans, even though the number of private pension plans in the United States has increased dramatically in the last 40 years from fewer than 1,000 in 1940 to almost 700,000 by 1982.

The number and percentage of workers theoretically covered by those plans also has grown. In 1979, about 35 million workers were participating in pension plans, according to government estimates.

According to the law's definition, Christine Clark was a participant in two pension plans, but never qualified for retirement benefits. The obstacle to her receiving a pension was the vesting requirement of the two employers for whom she worked for 32 of the past 35 years.

Clark went to work for the Liggett and Myers tobacco company's Richmond plant at age 19 in 1947. L&M had a pension plan, but the rule then, before ERISA took effect, was that an employe had to work for the company for 10 years after turning 35 before vesting -- qualifying for pension benefits.

Despite her 23 years working for the company, Clark had received credit for only seven years toward L&M's pension plan when the company moved its operation in 1970. When she decided to stay in Sandston, Va., where she lives, she lost her job and her claim to any pension benefits from L&M.

After doing odd jobs for three years, Clark went to work in the American Tobacco Company's Richmond factory. When that plant moved to Reidsville, N.C., in 1981, Clark again elected not to move. Since she had worked only 8 1/2 years for American, she is ineligible for pension benefits from that company.

At age 53, having already worked for 34 years, Clark has nothing to look forward to in her retirement years but Social Security. She is divorced and her only child, a son, helps her out from time to time, she says, but "he has obligations of his own."

Clark currently is unemployed, and unemployment compensation has run out, forcing her to live on the savings she had put aside for her retirement. When she looks ahead another 10 or 12 years to the time when she stops working, her future has none of the fantasies popularly associated with the "golden years." For her, retirement will mean getting by, but not much more. "I guess I could live on Social Security by stretching it," she said. "but the cost of living is so high."

Under ERISA, a company with a pension plan may require employes to stay with the firm for 10 years before their pension rights are vested or guaranteed. This provision operates on one level to encourage employes to stay with the firm in order to maximize their benefits. But this provision of the law, which often means that the employe receives no pension rights until the 10th year, when he or she becomes 100 per cent vested, also is a principal obstacle to many employes' ever receiving a pension.

"Our dynamic economy constantly changes," wrote Merton C. Bernstein, principal consultant to the National Commission on Social Security Reform, in a memo to the commission. When workers move into new jobs, that also often means that they have lost a job, said Bernstein, a law professor at Washington University in St. Louis.

The main threat to qualifying for pension benefits, Bernstein said, "is separation from the covered job. While employes (especially younger ones) leave jobs, jobs often leave employes of all ages." Plant shutdowns, Bernstein notes, are a major cause of job loss for employes.

The private pension system "is incapable of offsetting the impact of inflation or of protecting workers who change jobs frequently," says Alicia H. Munnell, an economist and vice president of the Federal Reserve Bank of Boston. Munnell, Bernstein and others point out that most companies do not index pensions for already-retired employes, so that their benefits are effectively shrunk by inflation.

"Moreover," Munnell says, "pension benefits are concentrated among highly paid people; low-wage workers receive almost no private pension benefits."

Under ERISA, companies with corporate pension funds are given three alternatives for vesting -- 10-year "cliff vesting" in which the employe's rights are fully protected, but only after 10 years of steady employment. Two other alternatives are permitted, offering gradual vesting over periods of 10 or 15 years.

Cliff vesting does not reflect the highly fluid nature of the American economy. In 1979, almost 60 percent of employes participating in pension plans had been working at their jobs for less than 10 years. Gradual vesting plans give workers something, but clearly only a fraction of their pension if they leave before vesting fully.

Roughly 8.7 million retired workers now receive private pensions. Department of Labor surveys show that an estimated 47 per cent of the private work force "participates" in pension plans.

Although some optimists predict that the percentage of workers receiving pensions will continue to increase, the President's Commission on Pension Policy expressed doubt about whether private pensions will continue to grow substantially.

According to government estimates, about half of those workers participating in a pension plan are vested. The President's Commission on Pension Policy estimated that just more than one-third of workers currently are entitled to private pensions.

Even after vesting, a worker who leaves a company for a new job often suffers a relative cut in retirement benefits. Although some corporate pension funds are designed so that benefits are "portable" -- enabling an employe to take them with him when changing jobs--many are not.

Harold Dripps, of Burnsville, Minn., for example, falls into that category. He worked for for a company for 19 years and was 100 percent vested in the company's pension plan when he left for another job.

In a letter to the Pension Rights Center, a Washington, D.C., public interest organization that lobbies for changes in pension laws, Dripps complained that he cannot get any of his pension money until he is 65.

The pension, Dripps said, is to pay "$323 at age 65. I will not be 65 until 1995 and my monthly pension will be the same $323 it was in 1979. With inflation, that will be worth very little."

Workers who stay with their employers in the present depressed economy may find their employer unable to stick with them. Cletus Conrad of Springfield, for example, worked for 21 years for the Thompson Dairy Company, a local firm. Although he had paid into a pension fund while he worked there, when the company went out of business in 1971, Conrad and his two brothers suddenly learned that they would not be receiving any pension and that the law did not protect them. The problem Conrad and his brothers had with this pension would be covered today by ERISA, which came too late to help them.

Conrad ultimately found another job working for a brick company in Virginia. After working for the company for 10 years, Conrad is vested in the company's pension program, but the company has suspended operation, telling employes it may be a year and a half or more before it reopens, said Conrad, now 57.

Conrad's pension rights are vested, and therefore protected and insured by an agency of the federal government created by ERISA, the Pension Benefit Guaranty Corporation. If his company does not reopen its doors, or if he does not return to it when it does, Conrad's benefits will be frozen at their present level, with no adjustment for inflation.

What may be a shortcoming in the pension system for one employe can be a windfall for another. "Social Security," according to Bernstein, "provides a transfer system from the upper paid to the lower paid. Private pension systems provide another transfer system, from the lower paid to the upper paid. The people who benefit are the upper paid and those with the longest service, which tends to be the same."

People who last in a company long enough to rise to upper levels of management "get large pensions because there are a lot of losers," said Bernstein, who compares it to pari-mutuel betting at a race track.

Critics of some pension plans contend that present tax laws subsidize higher paid employes by allowing companies to set aside current income for their retirement without paying taxes on it. In the tax increase bill approved by Congress on Aug. 19, significant changes were made for tax plans typically designed for smaller businesses and professional corporations.

The basic thrust of the changes is to make the plans more equitable for lower-level employes by shortening the vesting period and lowering the maximum pension levels.

For the most part, the changes relate to plans defined by law as "top-heavy" -- plans where more than 60 percent of the benefits are paid to executives, directors and highly compensated shareholders.

Top-heavy plans must vest employes either fully after three years or 20 percent a year over six years (the first year may be excluded).

The new law also requires the plans to pay a minimum pension to employes who are vested when they retire. Under present law, employers can integrate pension benefits with Social Security, subtracting the federal benefits from what they pay in retirement benefits. This mechanism often works to substantially cut or eliminate pensions of low-wage workers.

Under the change voted by Congress, "top-heavy" plans must pay a qualifying retired employe a minimum of 20 percent of his pension benefits regardless of Social Security benefits.

Although these changes apply only to top-heavy plans, some pension experts and congressional sources said that the changes made in the tax bill will increase the pressure to make similar changes across-the-board for other corporate pension plans.

Bernstein and other pension experts point out that any changes that improve benefits for retirees receiving less will mean either reducing benefits for those now getting more, or it will mean raising the cost of maintaining the plan.

Bernstein and other critics see ERISA and other changes as an improvement, but not a solution. Pointing to the upheaval that is transforming whole industries and bringing several large corporations to the edge of bankruptcy, Bernstein sees continuing and pervasive problems:

"A lot of people will tell you, 'Ah, well, we've solved most of the problems.' I don't think we have. Or they will say that this is a problem of blue collar workers. It's also a problem of white collar workers -- and managers."