Capitalization in mid-20th century British English

While reading the early "Thomas the Tank Engine" books (published in the 1940s and 50s in Britain) I was struck by the somewhat odd capitalisation used. Most of the text is capitalised as in modern English, but occasionally the author would capitalise odd nouns, such as in the following passage:

Thomas steamed back to the old buffers. He knew that bringing Lady back would be Really Useful. But he was nervous, too.

"Thomas" and "Lady" are capitalised as they are the name of railway engines, but I don't understand the capitalisation of "Really Useful". Is this the last vestiges of capitalising words to be emphasised, or is there another layer of meaning?

Solution 1:

As StoneyB suggests in a comment above, the striking capitalization style that A.A. Milne used in his stories and poems about Christopher Robin and Winnie-the-Pooh (which appeared in four volumes across the years 1924, 1926, 1927, and 1928) was very likely the inspiration for a generation (or more) of children’s books to use initial caps for emphasis. A few examples from the Winnie-the-Pooh oeuvre, courtesy of Winnie The Pooh Quotes:

“Don’t underestimate the value of Doing Nothing, of just going along, listening to all the things you can’t hear, and not bothering.“

Would you mind coming with me, Piglet, in case they turn out to be Hostile Animals?”

”Then would you read a Sustaining Book, such as would help and comfort a Wedged Bear in Great Tightness?”

The claim of Sellars & Yeatman’s 1066 and All That to such credit (or responsibility) is undercut by the fact that it was published in 1930.

Another (and even earlier) serious student of the capitals-for-emphasis school was George Ade. A representative paragraph from his work is this one from People You Know (1903):

Once there was a full-sized Girl named Florine whose Folks kept close Tab on her. Any night-blooming Harold who presumed to keep the Parlor open after Midnight heard low Voices in the Hallway and then a Rap on the Door. If Florine put on her Other Dress and went to a Hop then Mother would sit up and wait for her, and 1 o'clock was the Outside Limit. Consequently Florine would have to duck on the Festivities just when everything was getting Good. Furthermore she would have to warn Mr. Escort to behave himself when they drew near the House.

Solution 2:

This may by a joke copied (perhaps unconsciously) from the style of a very popular humorous book "1066 and All That: A Memorable History of England, comprising all the parts you can remember, including 103 Good Things, 5 Bad Kings and 2 Genuine Dates" by Sellars and Yateman, published in about 1930. See http://en.wikipedia.org/wiki/1066_and_All_That for more detail. In the book, the names of Important People or Significant Events are usually capitalized, as a parody of school-children making notes on a topic. The catch-phrases "A Good Thing" and "A Bad Thing" from the book are still sometimes capitalized for comic effect, and the "... And All That" catch-phrase in the title has been re-used many times in serious writing as well as in comedy.

The engines in the Thomas books are consistently described as "Really Useful Engines."