Complex sentence: JR Hokkaido is extending the Hokkaido Shinkansen from Shin-Hakodate to, planned to open by 2035, with tunnelling work on the Murayama tunnel, situated about north of Shin-Hakodate station; proposed to commence by March 2015; and be completed by March 2021.
Split into simpler sentences: JR Hokkaido is extending the Hokkaido Shinkansen from Shin-Hakodate to, planned to open by 2035. Tunnelling work on the Murayama tunnel, situated about north of Shin-Hakodate station is proposed to commence by March 2015, and be completed by March 2021.