The experiment mentioned in your PDF was done in 2013-14. You can find a mention of the same in the following page detailing IR's efforts in constructing SG LHB coaches.
click here
Even now, RCF is conducting trials for SG LHB coaches, but over the last 1 year, IR has shifted focus to equipping locomotives with HOG systems to power the rakes. From a maintenance perspective and other factors like construction cost, running speed etc, HOG/EOG based coaches are more economical than SG coaches. May be SG LHB coaches...
more... might become regular in the future, but as of now, IR does not have any plans to make these coaches mainstream. They will be restricted to experiments for a long time.