When our local tourist railroad – the Fillmore & Western – acquired its turntable from the abandoned roundhouse in Capreol, Canada, I was inspired to do some research into the turntable's history, as it appeared to have had a ten-foot extension added to each end at some point in its life. This led me to purchase
'Engine Houses & Turntables on Canadian Railways, 1850 - 1950' by Edward Forbes Bush. This is an excellent source of photos and technical information, as railroading practices in Canada closely parallel those in the U.S. A quick scan of this 160 page volume this morning failed to reveal the specific interior color description mentioned previously, but I'm fairly sure this book is the source of the information given above.