The famous Flying Scotsman pulls King Charles’ Royal Train through countryside before he was shown how the locomotive works.
His Majesty chugged into the market town of Pickering after a trip on the North Yorkshire Moors Railway, which is celebrating its 50th anniversary.
Charles then posed next to the famous 100-year-old engine before accepting an invitation from driver Chris Cubitt to climb on the footplate.
The King was later greeted by hundreds of well-wishers on an extended walkabout in the town, where one woman appeared to faint in the heat.
He also visited shops including a family butcher which sells Duchy of Lancaster produce before going to cool off at historic St Peter and St Paul’s Church.
Mr Cubitt, who started working on the railways in 1961, said of King Charles: "He's interested in everything. He's a good egg. He likes everything heritage."
"I invited him in for tea, but he said he couldn't come (but) he was a gentleman."
St Peter and St Paul's Church is famous for its medieval wall paintings.
Commissioned around 1450, the paintings, one of the most complete sets in Britain, were only accidentally rediscovered behind plaster in 1852.
As he signed the visitors' book, the King was told by the Reverend Gareth Atha that Queen Mary had visited the church in 1937.
Charles said: "I remember my great-grandmother very well."
