House Orien is ever trying to find ways to improve the Lightning Rail, and one such project is an attempt to discover "shortcuts" that the rail could take through Khyber. If they could find a viable, and reasonably safe, route through Khyber, it has the potential to massively reduce travel times across Khorvaire, and potentially allow rail travel to Aerenal or Xen'drik.
Orien Expedition No.2 were the 2nd expeditionary force sent to map out Khyber. Much like the previous expedition, they were lost to Khyber.