Mark Stafford's "Steam-Dinos" is a Lego fantasy with its own backstory:
“A spiffing way to go to war I decided as we powered through the veldt. Mr. Roberson’s patented Triterrortops steam powered terrible lizard replica was performing above the expectations it has been set by His Majesties Royal Calvalry Corp. My report to the Generals will be that the vehicle has proved more then adequate to combat the clone-vat monstrosities of the Zimbab bio-shamens.(sic)
Also: it really walks!