http://www.bcarchives.gov.bc.ca/cgi-bin/www2i/.visual/img_med/dir_160/a_09598.gif
The picture shows the roundhouse at Revelstoke BC, note the part of the turntable showing, It is totally decked in with timber. Makes sense given the amount of snow in the Revelstoke area.
However, a later picture of the Revelstoke yard shows the more conventional turntable with the bridge type structure. I assume that as the engines became larger all of the turntables changed as well and were rebuilt.
http://www.bcarchives.gov.bc.ca/cgi-bin/www2i/.visual/img_med/dir_152/g_01329.gif