What is a (Carriage) Trimer???

[CNW534]

A carriage trimmer installed and repaired the interiors of railway coaches.

Mark

[Dough]

I am looking through some old census information and I came across the term "trimer" as an occupation in 1850. After searching I saw this term in relation to both wagon makers and railroad employees. I also see both "carriage trimer" and just "trimer." Is there a difference? I see both a R R overseer as well as a wagon maker listed in the same district.