This collection of mailable vintage-photograph postcards documents a time when Montgomery County, Pennsylvania, was served by 140 miles of trolley lines. In the first half of the 20th century, a wide array of trolley cars rolled over Montgomery County's rails, from quaint open streetcars rumbling through borough streets to sleek 80-mile-an-hour trolleys sailing across open fields in Upper Gwynedd and Hatfield Townships. The cars had zero emissions, and some lines were powered by renewable hydroelectric power. Taking the trolley was a convenient, affordable option for those travelling and commuting in Montgomery County, nearby Philadelphia, and points beyond. Freight was also carried on board trolleys, with prompt parcel delivery service. Fortunately, many years ago, dedicated trolley fans had the foresight to aim their cameras at these unique vehicles, providing rare glimpses not just of the trolleys but also of Montgomery County's rapidly changing landscapes.