The protesters were against the pollution caused by Drax
Twenty-two environmental campaigners have been found guilty of obstructing a train carrying coal to Drax Power Station in North Yorkshire.
Protesters boarded the train carrying coal into the station in June 2008 after it stopped for two men posing as railway staff, Leeds Crown Court heard.
The defendants, including three from West Yorkshire, were protesting against pollution at the station in Selby.
Judge James Spencer QC said they would not face a custodial sentence.
Sentencing was adjourned to a date in September.
The trial, which was scheduled to last two weeks but only ran for four days, heard how the train was stopped by two men posing as Network Rail staff, wearing orange jackets and hard hats, who held up a red flag.
Moments later the train and a nearby bridge were scaled by the protesters wearing white paper boiler suits and carrying banners.
The protest lasted 16 hours, causing delays to numerous freight and passenger services.
During the protest coal was shovelled on to the track to stop the train moving.
The clean-up operation cost more than £30,000.
None of the defendants denied being on the train but they told the jury they did not believe they were doing anything criminal because they were trying to prevent climate change.
A statement from British Transport Police said that "in this case the activists involved took the activities too far and went beyond the bounds of lawful protest".