Yeah! The only kind of contribution I can make to this board!

The comment on trains on ballgowns cannot firmly pin down the date of Northanger Abbey to c.1798, because trains continued to appear in on ball dresses and walking dresses in Britain until about 1806, long after they had disappeared in France. Short trains were still fashionable on ballgowns into 1816!

However, by about 1806, it was less common to see trains on ballgowns. The fashion commentary makes it clear that a young woman wearing a gown with a train was making it clear that she did not intend to dance that evening, while the normal "dancing dress" was clear up to the ankle.

Trains came in two styles: one was the standard skirt that was simply extended in length in the back, the other was a separate garment piece which was attached to the gown at the shoulders in back. Pinning up a train was much like bustling up a modern wedding gown: you make a kind of pouffy fold at about mid-thigh level and pin up the excess skirt fabric so that the wearer doesn't step on it (or any of the other dancers). The shoulder train would most likely have been folded up and pinned at the waistline.

As for pins in sleeves, this was a fairly common way of making a puff at the shoulder - like bustling up a train, you would make a pouffy fold about midway between elbow and shoulder and pin it in place, to draw up the sleeve into a puff.

I really don't understand how all these women managed to pin themselves together and stay together all day and all night without scattering pins whereever they went, but it does appear from all the pin marks in the extant garments that this was the case.

Louisa
Mistress of the Garderobe