Translated and quoted from the article shown below. And a picture related to the article is also shown here.
http://www.chugoku-np.co.jp/News/Tn201101230059.html
Platform 0 at Shin-Yamaguchi station was abandoned due to the renewal of diagram on March 12th,2010.
Then, JR west decided to use it as the exhibition place of SL "Yamaguchi" , which is the train pulled by a steam locomotive.
According to the article, SL "Yamaguchi" will be exhibited on the track 0 only on the day its operation is out of service. Not only the exterior of the train but also the interior of it will be shown to visitors.
Reconstruction is scheduled to finish by this spring.