 Fleming had previously travelled to the US on the RMS "Queen Elizabeth"; the experience provided background information for the final four chapters of the novel.His trip had included a railway journey on the "Super Chief", during which he and Cuneo had visited the cab to meet the driver and engineer, and an excursion on the "20th Century Limited", both of which gave information Fleming used for Spang's train, the "Cannonball".Fleming had a long-standing interest in trains and following his involvement in a near-fatal crash associated them with danger.