WASHINGTON — A majority of freight railroads and passenger trains will not be able to meet a year-end deadline to install technology that prevents trains from exceeding speed limits and helps avoid collisions, the Federal Railroad Administration said Friday in a report to Congress.

Congress set a deadline of Dec. 31 for freight and commuter rail companies to install the technology, which is known as positive train control, after a California passenger train derailed in 2008, killing 25 people.

But the report, which was provided to the House and Senate Appropriations Committees, said few railroads were on schedule to meet the deadline.

The largest railroads would only have 39 percent of their trains fitted with the technology by the end of the year, the report said. In addition, just 34 percent of the employees who need to be trained on the equipment would be ready by Dec. 31.