anybody seen info regarding tariff impacts on cross-border locomotive and railcar movements? I'm not talking about the cargo aspect.

CN is very reliant on Canadian owned units. That is offset by most having been made in the USA. Might seem weird but they could be dinged by using them in Canada.

Does the CNIS, CNA et al car fleets regain their significance? There is railcar manufacturing in Canada. Those reporting marks were used on cars for which duty had been paid.