An evolution from previous streetcar models, the Class 1s were designed with artistry, state-of-the-art technology and San Diego's unique climate in mind. Under Spreckels' guise, the engineers of SDERy drafted up plans that took elements from both the "California Car" and the "Closed Car" designs and refashioned them into a new, modern transit fleet. Their plans were sent to the Saint Louis Car Company (SLCCo) where these beautiful, Arts & Crafts-style streetcars were built and shipped out to San Diego. Ultimately, the Class 1 streetcars ran all over San Diego, from Coronado through Downtown, Mission Hills, Ocean Beach, North Park, Golden Hill, and Kensington. They even briefly served as a link to the U.S.-Mexico Border.