I had been wondering how to deal with the rather tight curvature of the timbers at the edge of the turntable pit. In my head, they were ties, with a scallop cut into them. That could work for the two outer tracks, but what about the middle track? It either gets no tie at the edge, or it gets a little filler piece. Also, would the scalloped ties be sufficiently robust, or would they need to be a wider timber?
So, I cast through my collection of turntable pictures, looking for inspiration, and ultimately found what I was looking for in Edward Bush’s Engine Houses and Turntables of Canada (thank-you Scott, once again for the loan of this fantastic resource). Above is a detail from a photo of Field to be found in the Public Archives of Canada. You can just make out that the timber at the edge is two layers of shorter boards, and they overlap like bricks.
Last night, I took a stab at reproducing this look in HO scale. Frankly, my pieces don’t fit together as nicely as the carpenters’ at Field. Maybe it’s worth a redo. although I am eager to get to laying rail.
Another result of this research and modelling is that I’m no longer sure that a concrete curb at the top of the turntable pit makes sense. If I were building a turntable for a new line, especially one that has pretenses of reaching beyond Golden Lake to connect with the Central Ontario Railroad, I would build it with expansion capacity. Making this curb from concrete would mean that when I build the new, larger roundhouse, I would have to chisel away that curb. Far better to make it from wood or just leave it off. It remains to be seen whether this line of thinking is going to bother me enough to do anything about it. It would certainly be risky to pull the styrene curb off, to say the least!