Tom's early invention, a lightweight electric car. While perhaps not as revolutionary as later creations, it demonstrates his early interest in and aptitude for electrical engineering and automotive technology. It's often the vehicle he uses for local travel around Shopton.

Tom improves upon the existing technology of the motorcycle, adding his own inventive touches to increase its speed and reliability. This serves as a more adventurous vehicle than the runabout.

Tom designs and builds a powerful and reliable motor-boat, showcasing his knowledge of naval engineering and internal combustion engines. He uses it for races and rescues.

Tom builds an airship, demonstrating his knowledge of aerodynamics and lighter-than-air flight. This marked a significant leap in his technological capabilities and opened new avenues for exploration and adventure. It's often powered by new forms of electricity and propulsion.

Tom improves upon the existing wireless telegraph technology, allowing for faster and more reliable communication over long distances. This highlights his understanding of electromagnetism and signal processing.

Tom revolutionizes railway travel with his powerful electric locomotive. This shows his engineering expertise and contributes to advancements in transportation.

Later series saw Tom developing technologies relating to atomic energy, space travel, robotics, and computing. In general, each adventure featured a unique and groundbreaking invention tailored to solve a specific problem or explore a new frontier. These included advanced aircraft, submarines, and even time-traveling devices (in some iterations).