Three of its employees have sued the Metro Transit Authority, charging that Metro maintains separate pay and retirement schedules that work to the disadvantage of newer employees.

In a complaint filed in U.S. District Court in Alexandria, Metro employees Richard B. Klein, Warren E. Shindle and Linda Armstrong ask that Metro pay schedules and retirement benefits be equalized for older and newer employees and that newer employees be reimbursed for the money they lost because of the different pay schedule.

When Metro took over the four area bus companies in 1973, they allege, it adopted a pay plan for the new employees it was acquiring in the takeover. Although the beginning and maximum salaries for employees in a given grade were the same, it took an employee 12 years to go from minimum to maximum under the new plan, while it only took six years under the old plan, the employees charge.

There also are inequities in the retirement plans for older and newer employees, the suit charges.

Metro adopted a single pay schedule in March as part of a reorganization. Nonetheless, the suit charges, 58 Metro employees are receiving different, more favorable, pay benefits to this day.

Bus drivers, mechanics and other Metro employees covered by union contracts are not parties to the suit. The three suing employees are asking for class action status for themselves and about 1,300 other Metro employees who, they say, have been similarly harmed.

Metro counsel John R. Kennedy declined to comment on the suit until he has had a chance to read it.