Not content simply with entertaining children, Thomas the Tank Engine is on much bigger mission – to be a ‘global force for good’.

The latest series of the animated TV programme features a female Kenyan train called Nia to teach young viewers about refugees.

A United Nations adviser worked on the storylines, helping to ensure greater equality and diversity on the fictional island of Sodor where the series is set.

The latest series of the animated TV programme features a female Kenyan train called Nia to teach young viewers about refugees

The show has featured numerous characters from around the world including Ashima of India

Nia was first seen in August in a Thomas movie but joined the show permanently last month after losing her home and being displaced.

UN women’s Africa programme adviser Tolulope Lewis-Tamoka told Radio Times she wanted the series to promote ‘leadership and economic empowerment’.

‘We see that Nia doesn’t have a home,’ she said. ‘So she has to stay in Sodor, where Thomas works side by side with her to get jobs done.

‘We’re able to bring the idea of a refugee into the mind of a young person without calling them a refugee – someone who looks different to you might end up being your neighbour and good friend.’

Yong Bao, from China, has also previously been featured on children's show Thomas & Friends

A United Nations adviser worked on the storylines, helping to ensure greater equality and diversity on the fictional island of Sodor where the series is set (pictured, Rajiv)

Two favourite engines, Henry and Edward, are being moved to make way for Nia.

The show has featured numerous characters from around the world including Ashima of India, Yong Bao of China, Rajiv of India and Charubala, a female controller from India who cuts a far more slender figure than The Fat Controller.

The new Channel 5 series will be broadcast in more than 110 countries. It is said to have been warmly received by the family of Thomas’s creator, Rev Wilbert Awdry.