When Dorval R. Carter Jr. returned to the CTA last month as the transit agency’s president, he had to temporarily give up a sweet pension deal that had paid him three-quarters of a million dollars in just five and a half years.

Taking advantage of a little-known early-retirement incentive offered by the CTA, Carter left his second stint with the agency in 2009 and started collecting a $137,229-a-year pension the same month he turned 52, records obtained by the Chicago Sun-Times and Better Government Association show.

Carter didn’t retire, though. He moved to Washington, D.C., to take a post as a top lawyer in President Barack Obama’s U.S. Department of Transportation, where he would rise to the post of acting chief of staff, making $146,450 a year.

Double-dipping as a federal government official while also collecting a pension from the CTA allowed Carter to take home a combined taxpayer-subsidized income that reached $283,679 a year, records show.

Now 57, Carter collected $754,762 in pension payouts between November 2009 and this April, when he accepted Mayor Rahm Emanuel’s offer to return to the CTA for his third stint there, this time as its $235,000-a-year boss.

His salary — which the CTA says is in line with other big-city mass-transit system chiefs — is $20,000 a year more than his predecessor, Forrest Claypool, made. Claypool is now Emanuel’s chief of staff.

Carter has to temporarily forgo his pension now that he is once again a CTA employee, but he will be able to start collecting it again when he leaves the agency.

He’d worked for the CTA from 1984 to 1991, then, after working for the Federal Transit Administration, returned in 2000, staying until he accepted the early-retirement deal in 2009.

That amounted to a total of 16 and a half years with the CTA. But he was able to get a pension based on nearly twice that — 30 years of service — because the CTA, hoping to save money by encouraging higher-paid employees to retire early, allowed him to get credit for the nearly eight years he’d worked for the federal government and to buy credit for additional time.

Carter had been making contributions to the CTA Employee Retirement Plan — the pension plan for rank-and-file transit workers, who typically would be expected to retire by 65.

He also was vested in a separate “supplemental retirement plan” offered to CTA executives.

In 2008, the CTA board decided to close the supplemental plan for executives and offer them the early-retirement incentive. It offered a “voluntary termination program” allowing about 150 executives like Carter to move the money they’d put into the CTA’s regular pension fund to the supplemental plan if they agreed to retire by June 30, 2011.

There were pluses and minuses to the offer.

CTA execs agreeing to retire would have to give up a potentially lucrative benefit promised by the agency’s regular pension fund and most other government pension plans in Illinois — annual cost-of-living increases.

But they could boost their pensions by rolling in time served in other government jobs and by buying up to five years of additional credit. Also, many of them could start collecting immediately, regardless of age.

Sixty-nine employees took the deal, including Carter.

He signed up on Feb. 13, 2009 — one day before the deadline.

He missed a separate deadline, though, to request credit for the time he worked for the Federal Transit Administration, records show.

Participants were required “to request credit for governmental service within 18 months after becoming eligible to do so,” Michael Virgil, a lawyer advising the CTA, wrote to agency officials on April 13, 2009. “Mr. Carter is beyond this period.”

Despite that, a CTA retirement board allowed Carter to pay a $17,334 penalty “because of late application” and still get the credit for the time he worked for the federal agency.

The three-member supplemental retirement plan board that made that decision included Theresa Mintle, a CTA official who would go on to become Emanuel’s first chief of staff. Mintle’s cousin — former Mayor Richard M. Daley — appointed Carter’s late father, an obstetrician, in 1990 to an unpaid seat on the Illinois Medical District Commission, a governmental agency that oversees development within 560 acres on the Near West Side near the University of Illinois at Chicago.

CTA spokesman Brian Steele says Mintle and the board didn’t give Carter any special treatment. “Multiple employees” missed the same deadline and paid penalties because of confusion about the program’s rules, according to Steele.

Carter ended up transferring $58,778 he’d contributed to the regular CTA pension plan to the supplemental plan. And he wrote two checks totaling $186,075 to cover the penalty and buy additional pension credit — bringing the total amount he paid in toward his pension to $244,853, records show.

It was a good investment. The $754,762 he already has collected in the five and a half years before returning to the CTA amounts to more than three times his pension contributions.

“He signed up for a program that dozens of his colleagues signed up for as well,” says Steele.

Steele also says Carter had no role in creating the early-retirement plan.

But records show that Carter, who declined interview requests, sent a memo in November 2008 to then-CTA president Ron Huberman’s chief of staff, Lydia Murray, recommending the CTA board approve the program.

Steele says Carter — who ended up with the biggest pension under the program — was just passing along that recommendation from Dennis Anosike, the CTA’s chief financial officer, in his role as the agency’s executive vice president for operations support.

Anosike, who signed the memo, is now collecting a yearly pension of $105,510 through the early-retirement program, records show. He couldn’t be reached for comment.

In 2008, Anosike projected the program would save the CTA $3.6 million a year.

But Steve Mayberry, another CTA spokesman, says it’s unclear how much savings there might have been because no one at the agency has looked at that since the program was approved. Nor is it clear how that estimate was calculated, according to Mayberry.

“The memorandum dated 11.12.08 from Dorval Carter to Lydia Murray implies that actuarial projections were made,” Mayberry wrote in response to questions. “But the methodology for creating the savings estimate is unknown. CTA records show no cost-savings analysis having been performed since 2008.”

Steele adds: “All the individuals who put this plan together are long gone from the CTA.”

Even as Carter’s annual income from his CTA pension and federal salary topped $280,000, court records show the Hyde Park condominium he and his wife owned went into foreclosure in 2013. A judge dismissed the case earlier this year after the Carters agreed to sell the condo.

“This has no bearing on Carter’s 30 years of experience and his record of accomplishment in public transportation at the municipal and federal level,” City Hall spokesman Adam Collins says. “Dorval Carter has earned the respect and praise of transit experts in Chicago and across the country, and he will be a great asset to the people of Chicago.”

At the CTA – which provides train and bus service in Chicago and inner-ring suburbs – Carter oversees an annual operating budget of more than $1.4 billion.