I still find it hard to believe that rail shipment of crude oil is economical in any sense; a pipeline has got to be more efficient. Yet it appears we are shipping Bakken crude by rail to refineries on the east coast.
It is 2~3 times the cost typically. But it also allows more flexibility in where it is shipped. In some cases, they can pay more to ship but ship to a difficult place to reach with a pipeline like to New Jersey. There they are competed with oil imported from OPEC and the like rather than domestic served pipelines.
Domestic Crude Oil First Purchase Prices by Area
http://www.eia.gov/dnav/pet/pet_pri_dfp1_k_m.htm
Note, some of the difference are due to quality, not just location.
Domestic Crude Oil First Purchase Prices by API Gravity
http://www.eia.gov/dnav/pet/pet_pri_dfp3_k_m.htm
It makes it hard to find a simple comparison, but such has always been the case in the oil market.