A high capacity cargo/container dolly. The cargo/container dolly includes retractable side stops that actively retract a roller linkage assembly upon retraction of the retractable side stops rather than relying on passive gravitational forces for the retraction. In some embodiments, the retractable side stops are configured to avoid hold up on the cargo during retraction. The retractable side stops may be coupled to a retraction mechanism that may be actuated from either side of the cargo/container dolly, as well as from one or both ends of the cargo/container dolly. The dolly may include aspects that accommodates dynamic loads that occur during transport to mitigate inadvertent retraction of the retractable side stops or spurious release of catch assemblies that retains cargo on the dolly. The dolly may also include self-locking roller assemblies that release only in the presence of cargo, and deck modules that protect the deck roller from road spray contamination.