An overhaul of Thomas the Tank Engine will see two male engines turfed out to make way for female characters.
Henry and Edward will be moving out of Tidmouth Sheds to make way for Nia, an orange engine from Africa, and Rebecca, a yellow-coloured engine.
They will join Emily, the other female engine, as well as the boys Thomas, Percy James and Gordon.
And the tradition of Liverpudlian narration – which first began with Ringo Starr – will disappear, as well as the theme tune with its roll-call of engine names.
Thomas the Tank Engine will be leaving his home for half the the 26 new episodes as he embarks on adventures throughout the world
But the the most dramatic change will be Thomas leaving his home on the Island of Sodar as he embarks on adventures across the globe.
Mattel, the US toy giant that owns rights to the much-loved show, collaborated with the United Nations to help meet the organisation’s Sustainable Development Goals.
The storylines have been written to meet five of the goals: quality education, gender equality, sustainable cities and communities, responsible consumption and production, and life on land.
Mattel said the changes are a ‘groundbreaking refresh’ and is based on extensive market research with hundreds of parents and their children.
Nia, an African engine who will teach Thomas a lesson about the meaning of friendship, will join the show for the new series
The show had previously come under fire and was criticised as sexist, classist and anti-enviromentalist.
But its creators have introduced small changes in recent years, including the addition of Japanese engine, Hiro.
The overhaul, which begins in 2018, is the most significant transformation since the TV version first broadcast in 1984.
The shows are based on the books of Rev Wilbert Awdry, who made up the stories to entertain his son, Christopher, who was ill with measles.
Series producer Ian McCue said the team could not ‘sustain’ episodes that were based in Sodor any longer
However, Thomas and Friends is today facing competition from US cartoons, meaning the show has to evolve.
The new series, which airs in 2018, will ‘break the fourth wall’ as Thomas narrates the series himself and talks directly to the viewer.
Series producer Ian McCue said the team could not ‘sustain’ episodes that were based in Sodor any longer.
‘We wanted him to disover new things, and for the first time he will be leaving Sodor and England,’ Mr McCue told the Telegraph.
‘We couldn’t have him encountering a new animal in Sodor every week, but now he can meet kangaroos in Australia, tigers in India, pandas in China.’
Mr McCue said that while other female engines had featured on the show previously, they had ‘disappeared into the background’.
‘We’re not making these changes for the sake of it. We know that a lot of girls love the show. The audience on [Channel 5’s] Milkshake is 50:50,’ he added.
It comes after Labour MP Mary Creagh complained that Thomas was perpetuating ‘negative sterotypes’ — arguing it needed more female engines.