In the US, there is almost no room for advancement. Every year comes with a "less than the" cost of living raise and even the slightest little hiccup causes the upper class to declare no bonuses for the peons. Individuals who are passionate and knowledgeable are discouraged and rarely given the resources they need to improve themselves or the company.
Small decisions are bogged down with red tape and the inclusion of individuals who don't understand the details. Large decisions are made in upper management by people who don't know what's needed on the ground. Over and over you'll hear "upper management has approved this process". Any criticism of these decisions, or bringing light to their deficiencies, is considered "making noise" and is quickly squashed.
Don't anticipate being formally trained, or even cross trained between groups. Silos are ever present and exceptionally strong. The company pats itself on the back that they're "One Team", but that's just a way of shutting employees up when someone complains that another team isn't pulling their weight or is screwing things up.
When you leave the company, they magically change the vacation policy. Suddenly, even though the vacation policy is based on years of service with no accrual, they will pro-rate your vacation when you leave. If you have 3 weeks of vacation on January 1st and use it all in February, and then leave in March, CN will determine that you owe them a good portion of your used vacation time and will dock your last check(s). That's if you're lucky. If you're me, you're still waiting for your last check.
IT has "pillars" that they cling to, but none of those pillars have anything to do with being competent. So long as you're friendly and can repeat keywords, CN will love you.