On most railroads, section gangs handled only roadway maintenance. Separate Bridge & Building gangs were responsible for structure and bridge maintenance. B&B gangs often moved around to projects over an entire system - sometimes living in camp cars while section gangs had a defined "section" often working out of a "section house" and later out of maintenance bases. Both crews worked under the overall direction of the Division Chief Engineer, who was charged with annual updates to the ICC Valuation Reports. The ICC required detailed records on railroad assets and physical property. That's why we have the legacy of the "val maps" which serve as a record of where things were.
Railroads also had C&S (Communications and Signals) Departments, Maintainers in the C&S department were responsible for keeping railroad-owned telegraph lines in order and later, when automatic crossing protection devices came along, they had responsibility for inspection and repairs on those devices.