Definition: Roof Structures

Early streetcars had a two-level roof with small windows that provided light and ventilation around the perimeter. Such roofs referred to as a “monitor” or “deck” roof if they had square ends or a "railroad" or “clerestory” roof if the ends curved down at the end (like an early railroad passenger car). The two level roof provided ventilation and illumination and lent much of the classic appearance to early trolleys. Later cars typically had a smooth curved, single level “arch” roof with ventilators mounted along the surface. In either case, the roof structure was typically narrow wooden boards mounted on supporting framework, with the surface covered by painted canvas.

This Lowell open car has a monitor roof.	This San Francisco car has an arch roof.	This early single truck car in the Boston suburbs has a railroad or clerestory roof.