 In the area of pension funding, because of limitations originally imposed by Congress, most Amtrak workers were traditionally classified as "railroad employees" and contributions to the Railroad Retirement system have been made for those employees.However, because the size of the contributions is determined on an industry-wide basis rather than with reference to the employer for whom the employees work, some critics, such as the National Association of Railroad Passengers, maintain that Amtrak is subsidizing freight railroad pensions by as much as US$150 million/year.In recent times, efforts at reforming passenger rail have addressed labor issues.