They're not actually "assigned branches" of the police, they're private police. The US/Canadian railway police are not government employees, they're employees of the Class I railways and deputized with general law enforcement powers. They're spiritual successors to the old timey Pinkertons.
Two of the biggest are Canadian National Police and Canadian Pacific Kansas City Police -- and those two are deputized, in both Canada and the US, with Federal, State and Provincial police powers. Despite being railway employees they can cite you for, e.g. speeding if they catch you doing so. Either on or off railway property.
Two of the biggest are Canadian National Police and Canadian Pacific Kansas City Police -- and those two are deputized, in both Canada and the US, with Federal, State and Provincial police powers. Despite being railway employees they can cite you for, e.g. speeding if they catch you doing so. Either on or off railway property.