Class - a matter of comfort, speed... or Both?
But it would be a mistake to say that the enclosed yellow "First Class" coaches were first-class only; whilst they provided the same level of accommodation as a Stage-Coach for "Inside Passengers", we have to remember that Stage Coaches provided both a "First Class/Express" and also setting down service. Entire trains were run of differant types of accommodation and whether they were Express or "setting down".
The timetable for June 1839 makes this distinction quite clear
By first-class train, four inside, Royal Mail Coach 6s 6d
By first-class train, six inside, Glass Coach 6s
By first-class train, six inside, Curtain Coach 6s
By second-class train, six inside, Glass Coach, 6s
By second-class train, Open Carriages 4s 6d
"First Class" and "Second Class" - not such a matter of accommodation, more of speed.