BNSF line near Louisville, CO

The old Colorado and Southern line from Billings to Denver, then down to Texas on the Fort Worth and Denver. Grain moving north to Seattle to on-load to ships to export to Russia are the hoppers. The oil tanks are heading north to the refinery's in Billings. The C&S BNSF sub division is for a large part loads north, empties south. 

The loaded open-top hoppers are hauling coal from Wyoming, to destinations south, east, or west of Denver.  The empties are returning to the mines.

You'd need to get close enough to the tank car trains, to be able to read the UN number on the diamond-shaped placard which is mounted near the corner of the car.  The placard will probably have a flame on it (indicating a flammable commodity) and the UN number is black, in a white rectangle in the center of the placard.  

1170 is ethanol;  1267 is crude oil;  1202 is diesel fuel;  1203 is gasoline.  A solid tank car train is almost certainly either crude oil or ethanol.  Most other commodities do not ship in large enough volume to warrant a whole train.

Great information. Thanks. I'll get close enough to the tank cars when it gets warmer! :-)

We get several trains a week through Sioux City, Iowa on the BNSF containing ethanol (from several producers) or oil from North Dakota. 

Dick