"Rail Romanesque" is set in a world where sentient train-like beings known as Railords coexist with humans. The story unfolds in Hinomoto, a nation divided into multiple regions, each governed by its own Railord. These Railords, modeled after historical steam locomotives, are revered as deities and play a crucial role in maintaining the balance and prosperity of their respective territories. However, as modernization threatens the traditional ways of life, the Railords face challenges to their relevance and authority.

The narrative centers on Aoi, a young girl who becomes the conductor of the Railord Raicho, a once-powerful but now neglected deity. Aoi is tasked with revitalizing Raicho and restoring her former glory. Alongside Aoi are other conductors and their Railords, each representing different regions and embodying unique personalities and abilities. The series explores their efforts to adapt to changing times while preserving their cultural heritage. Conflicts arise as rivalries between Railords escalate, and external forces seek to exploit their powers for personal gain.

The main characters include Raicho, a proud and determined Railord with a strong sense of duty; Aoi, her earnest and resourceful conductor; and a diverse cast of Railords and conductors, such as the elegant and composed Kiko and the fiery and competitive Hatsune. Each character’s journey intertwines with themes of tradition versus progress, loyalty, and the importance of preserving history in the face of modernization. The series balances lighthearted moments with deeper explorations of the Railords’ roles in society and their relationships with their conductors, culminating in a story that highlights unity and resilience in the face of adversity.