The Trans Mountain Pipeline transports crude oil, semi-refined and refined products in a series in the same pipeline. This process is known as “batching”. Think of it as a “batch train,” with one product following another product through the pipeline during a specific time period. It’s like a series of rail cars carrying different products moving in a sequence along the 1,150-kilometre pipeline.

Trans Mountain is the only pipeline in North America that carries both refined product and crude oil in batches.

On any given day, the pipeline is used to move different grades or varieties of petroleum. Products moving next to each other in the pipeline can mix. This mixing – or product interface – is minimized by putting the products in a specific sequence.



The products currently shipped in the Trans Mountain pipeline:

Product Type



Refined petroleum

Gasoline or diesel


Synthetic crude

Processed bitumen


Light crude

Conventionally sourced crude oil


Heavy crude

Diluted bitumen


More can be found about the properties of specific light, synthetic and heavy crudes here:

Other than refined products, each of these general product types can be blended or pumped individually as requested by shippers – Trans Mountain’s customers who own the products transported in the pipeline. Any product moved in the pipeline must meet tariff requirements, which include the requirement for products to adhere to technical specifications in order for them to be accepted for transportation in the Trans Mountain Pipeline system.

These rules specify that the product has:

  • A maximum temperature of 38⁰ C
  • A maximum density of 940 kg/m3
  • A maximum viscosity of 350 cSt (centistokes) at Reference Temperature
  • Maximum impurities (basic sediments and water-abbreviated BS&W) of 0.5% of volume
  • Maximum Vapour Pressure of 103 kPa (kilopascals)

Tariff rules and regulations are published online.