While there presently is not an auto terminal at the port, CP's web site states a willingness to construct a facility at the port of Saint John for the import/export of autos via Ro Ro vessels. Other east coast ports like Halifax, Davisville, NY/NJ, Baltimore, Charleston and Savannah do a thriving vehicle import/export business. Ro Ro vessels even call on the port of Boston occasionally for vehicle import (despite the port of Boston having ZERO rail service at this point).
"AUTOMOTIVE
Flexibility with design and spacing for automotive, with the ability to configure the terminal to suit the needs of customers including creating a Vehicle Process Centre (VPC).
Capable of handling roll-on/roll-off vessels, with the ability to load rail on-dock and convert existing general cargo space for automotive fleets.
Automotive compounds in Port Saint John allow vehicles to be easily distributed across the Maritimes."
https://www.cpr.ca/en/choose-rail/atlantic-gateway