[SnuffaBolshevik]

Too bad there's no mechanism to allow those car carriers to be attached to the rear of an oil tanker train.

[nascarnation]

Some research (I’m definitely not a rail expert) indicates that oil tankers are pretty heavy per car compared to typical freight cars. So the “typical” tanker train is pulling the max weight that the locomotives can handle for the grades to be traversed at the speeds required.

[Paladin2]

There’s more single track than there used to be, so trains are limited in length by the length of the passing sidings.