The benefits rules are a bit different than the pension rules which sometimes causes confusion. A post retirement spouse is not entitled to pension survivor benefits under the plan. However, If the retiree is eligible to a Travel Card and then marries or remarries after retirement, the post-retirement spouse is eligible for the Travel Card (train pass).
You can simply call our CN Pensions call centre at 1-800-361-0739, and request one. The Customer Service Agent will take the required information and let you know if anything further will be required to process the application.