WASHINGTON — Senators say they’re skeptical that freight railroads are doing all they can do to alleviate widespread delays preventing shippers from getting their products to market.

Officials representing the agriculture, auto and chemical industries told a Senate hearing Wednesday that shipping rates are 90 percent higher than  in 2002 but service has drastically diminished.

Edward Hamberger, the rail industry’s top lobbyist, said railroads spent $26 billion last year on new track and other capital improvements, and that shipping rates are the same level they were in 1988 when adjusted for inflation.

Sen. Maria Cantwell of Washington state, said she didn’t believe the $26 billion figure. West Virginia Sen. Jay Rockefeller called the freight rail industry “the most powerful, under-the-radar lobbying group” in Washington, but warned their support in Congress is ebbing.