About one-third of the nearly 200 Massachusetts Bay Transportation Authority employees who retired last year and began receiving a pension were younger than 55 and dozens were still in their 40s.
The Legislature passed a law in 2009 to curtail a rule allowing MBTA employees to retire after 23 years of work and collect pensions.
The Boston Globe reports that the law only applies to new hires, leaving many retirees who fall under the old rules and potentially collecting pensions for longer than they worked at the T.
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More pensioners -- 5,600 in total -- are collecting benefits than there are workers paying in.
MTBA's annual contributions to the pension system have more than tripled since 2007 from $30 million to $103 million.