The eastern portion of the line is the Empress Sub, from mile 0.0 at Mayne (west of Swift Current) to EOT mile 89.3, just west of Leader. From Leader to Bassano the track has been abandoned. The Empress Sub ended at Empress, on the Saskatchewan/Alberta border and the Bassano Sub ran back to the mainline at Bassano. West of Leader the land is very dry and did not grow a lot of wheat.
http://www.proximityissues.ca/Maps/RAC-2004-SK_sub.pdf
Around Cabri there is or was a spur to a Sodium Sulphate mine at Snakehole Lake. http://www.saskschools.ca/~gregory/sask/na2so4.html
From Leader a line runs south to Ingebright Lake, which has either Sodium Sulphate or Potash.
http://www.salinesystems.org/content/1/1/10/figure/F8
Tatans is hiding somewhere in Saskatchewan and may know more.