Through a coach window

[Ronaldo47]

Here's another one with obviousy mocked-up scenery, an LMS compartment from 1928, which does clearly show the type of double sliding door then used. The great difference in illumination between the outdoors and the compartment interior would be impossible to photograph. While chemical reducers (Farmer's reducer was a common type)  were/are available to reduce the density of over-exposed parts of a negative, correct exposure of the interior would over-expose the exterior far too much for reducers to rectify. 

Taking a straight picture out of doors would result in considerable over-exposure of the exterior, as in this one of another LMS compartment.

 

This is how most of the photos of railway carriage interiors appear in my various books on  railways.

 

In the second  photo the shadows are consistent with the use of flash. These days it is not always appreciated just how slow most films were pre-war. I have a book on photgraphy published in 1948 that incudes a table of film speeds where the fastest is equivalent to only 64 ASA (ASA was not used in the UK at that time, and speeds were given in terms of H&D, Scheiner, and DIN).

Edited April 3, 2021 by Ronaldo47
deletion of duplicate of photo, typos