Sabotage on the Solar Express

This fifth standalone book in the middle-grade Adventures on Trains series by M. G. Leonard and Sam Sedgman finds young sleuth Hal Beck hurtling across the Australian Outback while trying to figure out who sabotaged the maiden voyage of a new train before it explodes!
When artist, train enthusiast, and sleuth, Hal Beck, and his travel journalist uncle, Nat, are invited to be on the first ever ride of the Solar Express train in Australia, he couldn't be more excited! The new train is the result of a worldwide contest held by tech billionaire August Reza, whom they met on a trip in America. And it's even more exciting to learn that the train's engine was designed by fourteen-year-old prodigy Boaz Tudaweli.
Once Hal and Uncle Nat connect with August and his daughter, Marianne, she confides in Hal her suspicions about a gift her father received. At first, it seems there's nothing to it. But when things start to go wrong even before the Solar Express has left the station—and get much worse when the ride begins—Hal, Marianne, and Boaz must investigate. Can they figure out who's behind everything before the Solar Express goes completely off track...and possibly explodes?