I haven't seen any other mention of this: the July 2013 issue of Continental Modeller (which just showed up at my local Barnes and Noble last week) has an eight-page profile of the Setagaya line in it, with lots of photos.
CM occasionally profiles Japanese layouts or railways, which is one reason I pick it up (the other is that there is a lot of very creative modeling of European lines described, so it's a good source of inspiration).