TransCanada spokesman Shawn Howard said in response to email questions rail delivery of oil is useful for smaller volumes over shorter distances.
"Pipelines and rail continue to be complementary parts of the transportation equation," he said Thursday.
The Canadian pipeline company announced Wednesday the first volumes of crude oil were delivered through its Gulf Coast project, a pipeline running from Cushing, Okla.
Russ Girling, president and chief executive officer at TransCanada, said in a statement Wednesday the 487-mile pipeline is a "critical" piece of U.S. energy infrastructure, which he said was designed in part to alleviate transport bottlenecks brought on by the increase in North American crude oil production.
The pipeline is the U.S. leg of the Keystone XL pipeline from Canada, which requires a federal permit to move forward. Howard said rail was an important option in the interim.
"With delays in the approval of some pipeline infrastructure, increases in the distances and volumes of oil being transported by rail has gone up significantly, but that does not change the fact that it is much safer and more cost effective to move larger volumes of products like oil longer distances by pipeline," he said.
A series of derailments of rail cars carrying crude oil has raised questions about the safety of that delivery option.