Complex sentence: The Lötschberg axis, with the new Lötschberg Base Tunnel in the Bernese Alps is currently being constructed by the company "BLS AlpTransit Lötschberg AG".
Split into simpler sentences: The Lötschberg axis, with the new Lötschberg Base Tunnel in the Bernese Alps. It is being constructed by the company "BLS AlpTransit Lötschberg AG".