All 29 protesters who boarded and chained themselves to a coal train headed to one of Europe's largest power stations are in custody, British Transport Police said.
The protesters, who are mainly from London, the South East and Manchester, would be interviewed during the course of the day, a BTP spokesman said.
The protesters surrounded and stopped the train a few miles from its destination, Drax power station in North Yorkshire, on Friday morning.
The spokesman said the last protester was removed from the train shortly after midnight.
Many of those arrested had to be cut free after chaining themselves to rail vehicles and a bridge, but there were no reported injuries.
The spokesman said the train had been moved and the coal removed from the tracks, which were handed back to the rail operators at 6am.
He said police officers would remain at the scene to carry out further searches.
The demonstrators had occupied the first two trucks of the 21-carriage train, carrying 1,000 tonnes of coal, and unfurled a 15ft long yellow banner bearing the slogan: "Leave It In The Ground!".
The train was halted on a bridge over the River Aire close to the village of Carlton, near Goole, North Yorkshire.
No charges had yet been made.
