It is uncertain when the first crude oil pipeline was built. Credit for the development of pipeline transport is disputed, with competing claims for Vladimir Shukhov and the Branobel company in the late 19th century, and the Oil Transport Association, which first constructed a wrought iron pipeline over a track from an oil field in Pennsylvania to a railroad station in Oil Creek, in the 1860s. Pipelines are generally the most economical way to transport large quantities of oil, refined oil products or natural gas over land. For example, in 2014, pipeline transport of crude oil cost about $5 per barrel, while rail transport cost about $10 to $15 per barrel. Trucking has even higher costs due to the additional labor required; employment on completed pipelines represents only "1% of that of the trucking industry.".