Trackmaster Revolution (TMR) New releases

If it helps any, Super, I believe a search of the title "Sir Gillemere" (or "Sir Gillemere locomotive" as the search, to be precise), may bear some results.

I ran through the LSWR N15 class page on Wikipedia, the class also known as 'King Arthurs', and this little excerpt might shed some light on Merlin:

In another wartime experiment, Bulleid fitted No. 783 Sir Gillemere with three thin "stovepipe" chimneys in November 1940.[46] These were set in a triangular formation to reduce visibility of exhaust from the air in response to attacks made by low-flying aircraft on Southern Railway trains.[44] The "stovepipes" were reduced to two, producing a fierce exhaust blast that dislodged soot inside tunnels and under bridges.[46] The experiment was discontinued in February 1941 and the locomotive re-fitted with a Maunsell King Arthur chimney.[44]