What is an example of “trust-busting” that theodore roosevelt enforced?

It is "regulating a rail road or any stuff like that"

One example of “trust-busting” that Theodore Roosevelt enforced was that "He broke up the Northern Securities Company," since the goal was to eliminate illegal "collusion" in order to support market competition. 

Protecting and assisting  u.s. citizens  living or traveling abroad; assisting u.s.  businesses  in the international marketplace; coordinating and providing support for international activities of other u.s. agencies (local, state, or federal government), official visits overseas and at home, and other diplomatic efforts.keeping the public informed about u.s. foreign policy and relations with other countries and providing feedback from the public to administration officials.providing  automobile registration  for non-diplomatic staff vehicles and the vehicles of diplomats of foreign countries having  diplomatic immunity  in the united states