In one of the final scenes of Lyon on the Inside, as well as the series, our hero and heroine are captured by the “murderer” who has taunted Lord Macdonald Duncan’s family for nearly a year. Lord Aaran Graham, our hero, and Lady Freya Cunningham, our heroine, are tied to the joints of a moving carriage, but is that possible? Here is my answer.

In Regency-era coaches, iron plates, hoops, bolts, and screws were fundamental components used to secure the various wooden parts of the carriage body and undercarriage, ensuring structural integrity and durability. 

Key Uses of Iron Plates and Joints

Securing Joints: The junctures where wooden components met were critical stress points. These were “cemented by white-lead and oil, and secured by iron hoops, plates, bolts, and screws” to prevent the wood from shrinking, separating, or breaking during movement.

Carriage Framework (Undercarriage): The entire framework supporting the coach body, known as the “carriage,” was a composite structure of wood and iron. This design was essential for resisting injuries incurred during travel on often rough roads.

Axle Integration: Iron was used for the axletrees, which were situated in grooves within wooden crossbars beneath the carriage body. The wheels revolved around the ends of the iron axles.

Suspension Systems: The Regency era saw innovations in suspension, largely reliant on iron and steel components.

C-Springs: These curved springs, made of overlapping plates, attached to the carriage body via strong iron work, replacing earlier, more primitive suspension methods.

Elliptical Springs: Invented around the start of the Regency period (1804), these springs were composed entirely of two sets of overlapping steel plates bolted together in an elliptical shape. This innovation provided a smoother and more stable ride.

Specialized Designs: Specific carriage types featured distinct ironwork:

Crane-neck Phaetons: These vehicles featured a heavier construction of iron beams and hoops in the undercarriage, which allowed the front wheels a greater turning radius.

Shifting Rails: These were detachable iron pieces, often oval-shaped, that attached to the rear seat to allow a carriage top to be removed while remaining somewhat organized.

Protective Gear: Even the post boys who rode the horses (postilions) instead of a coachman on a box seat wore iron guards on their right leg and foot to protect against injury from the center pole between the horses. 

Overall, iron plates and joints were essential for both the structural integrity and the technological advancements (like improved suspension and steering) of Regency-era coaches.

Geri Walton tells us, “Coachbuilding also meant that carriage builders also needed to ensure carriages possessed joints that would not shrink or separate with use. These junctures or joints were ‘cemented by white-lead and oil, and secured by iron hoops, plates, bolts, and screws.’ Cross bars, which had grooves to accommodate the axletrees made of iron, were placed below and passed from one wheel to the another. ‘Each end of it [was] placed in the nave of the wheel, and it was upon that the wheel revolve[d].'[The Book of Trades, Or, Circle of the Useful Arts, 1837, p. 287.] – This is an excellent source for those of you who wish more detailed information.