The father-of-two dropped into the Bombardier factory, who are currently making trains for the new Crossrail service, the Elizabeth Line.
The 34-year-old got to test his driving skills when he was given the opportunity to drive one of the trains on a test track.
Racking up 30 miles per hour, he remarked, "George would love it."
Chris Brittan was the dynamic test track driver at the site who showed Wills the ropes.
"I was telling him the functionalities of the train," the 32-year-old explained. "He was saying that George would love it, he would be excited about seeing his dad driving."
And young George would have been mighty proud of his dad, with the train worker commending the future King's skills on the track.
"He was nice and controlled. We took it up to 30 miles per hour. He was doing all the driving. He said it's easy to drive, it's nice and smooth."
And William clearly had a fabulous time.
Telling a group of locals,“I got to drive a train this morning, which I never thought I’d do. Never thought I’d get let loose on that."
“The horn was great, very noisy, so obviously I kept wanting to sound it. I was like a little kid!”
While in Derby, William also dropped by the Rolls Royce factory and a local charity, the Padley Centre, which supports those with mental illness and local homeless shelters.
During his visit, Prince William participated in a pottery group and helped with the arts and craft.
“I’m the least arty in my family but I’m up for it!” William said, laughing.
It's a different story for his wife.
Earlier this week, Prince William presented illustrator Johanna Basford with an OBE.
Speaking of the honour, Johanna revealed she had a fan in Duchess Catherine, who loves the artist's Secret Garden colouring book.
Kate's artistic hobby is fitting, after all she is renowned for her love of art - having studies art history at the University of St Andrews. The Duchess is also an avid photographer, famously snapping her young family for several official photos.