Pipelines, the unseen carrier, are used for the transportation of petroleum, petroleum products, gas and certain chemicals. Pipelines transport enormous quantities of petroleum, gasoline, chemicals and other products, sometimes over long distances. Pipeline transportation requires little labour and is relatively trouble-free because it provides reliable and low-cost transportation. However, it has two principal drawbacks: pipelines require an enormous amount of capital to establish; and they are seldom efficient unless large quantities of product are moved from a single point of origin to a single destination over a long period of time. Pipelines are also used for the transportation of bitumen from Alberta oil sands projects.