Watercolorist Trevor Chamberlain shared the following recollections about one of his heroes, Jack Merriott, whose work he saw when traveling to London by train:
"Back then, in the glory days of steam engines, the railway companies commissioned some of the leading watercolour painters of the day, including Jack Merriott, Rowland Hilder and Charles Knight, to depict scenes from all around Britain to be displayed as prints in the passenger compartments. These prints always had a long, narrow format and were usually panoramic landscapes. I would clamber into the carriage wondering which ones I was going to see, and I got to know them all."
Above is Merriott's poster of Aberystwyth, the historic market town in Wales.
Here is the approximate view as seen by the camera, a good deal duller and more spread out horizontally.
Here is Merriott's preliminary watercolor study painted on location, with lines for scaling it up to the final painting.
Images from Robert Kirk's blog
Travelling Art Gallery (selection of all of Merriott's Carriage Prints)
Merriott's book on watercolor can still be found inexpensively: Discovering watercolour;: A comprehensive home study course.
Chamberlain's watercolor book is harder to come by, but it's also excellent:Trevor Chamberlain: Light and Atmosphere in Watercolour