Looking on Google Maps I found what looks to be a old rail line that is not shown in my SPV Dakotas and Minnesota Railroad Atlas. The line seems to start in Newport off of CP and BNSF's main line and heads due North through Maplewood, over a purpose built looking causeway, across UP's Altoona Sub., through N. St. Paul, north to White Bear Lake, although it seems to end straight on the shore of White Bear Lake. On the South End it suddenly takes a turns and heads west towards the Mississippi. Could have Rock Island wanted to get part of the White Bear Lake tourist trade and planned to build a line from their connection to CP/BNSF's main line off of the Rock Island Tole Bridge.
This is the link-check it out.
http://maps.google.com/maps?f=q&source= ... 8&t=h&z=16