With the construction of Keystone and Line 3, it will be decades before we'd need a Trans Mountain pipe in the most optimistic forecast. In the meantime Notley can ship all the tar she wants in Neatbit or Bitball rail cars -  far safer than dilbit by pipe. Trans Mountain investors are looking at a 100% loss of their cash.

Google "bitumen-balls-pellets-pipelines-rail-train-transport-energy-alberta-technology"

Instead of causing $billions in cleanup costs from small spills like Kalamazoo, a damaged Neatbit/bitball carrier holds the solid tar in its hull. If selfdriving EV's collapse the market for this dirtiest of all petrol products as most economists predict, the neatbit/bitball carriers can be converted to carry enough grain to feed the world.

Dilbit is an environmental poison with deadly uncleanable consequences if spilled.   Alberta would  certainly object if  BC got a contract to pipe liquid arsenic or deadly CO2 from its mines to a legal disposal site in Calgary.