Passengers at Newcastle Central Station have been walking over a "lawn" to catch trains.
The event highlighted train travel's green credentials
The concourse area of the Grade I listed building has been carpeted with turf to convince commuters of the environmental benefits of rail travel.
Operator GNER hopes the one-day stunt will persuade people to take its services to London instead of flying.
The firm says a flight to the capital will emit five times more carbon than a rail journey.
John Metcalfe, chief executive of GNER, said: "Train travel is the greenest way to travel from Newcastle to London and it is also often the cheapest and quickest, compared to plane or car."
The grass will be removed at 2300 BST on Monday.