Carriage number
Also: vehicle number, carriage, coach number
Each carriage has its own number, painted on its side and usually by the doors inside.
Example
Carriage 40703, seat C23
An example.
Unlike the coach letter, which can change from day to day, a carriage’s own number stays with it for life. It’s usually five digits.
No open data feed says which carriage you were in, so Trainiac asks you. With the number and your seat, Trainiac can tell when you, or a friend, have sat in that exact seat before.
In Trainiac
Carriage and seat on a journey.