In 1937 the Southern Pacific trumpeted a new train in full-page magazine ads:
Let us stand by the tracks of Southern Pacific's Coast Line, as thousands now do every day and listen. Suddenly from far off comes a musical note, rising. Round a curve flashes a streak of color. Here comes the Daylight, the most beautiful train in the West!
The Daylights linked Los Angeles and San Francisco "in a glorious daylight trip, streaking along the Pacific Ocean for more than a hundred breathless miles." Travelers were invited to "Step inside the Daylight and see the beauty and luxury that have already won the West. Notice the wide, soft seats in the coaches. They are cushioned with sponge rubber and turn to face the extraordinarily large windows." Presenting a glorious streak of orange and red from locomotive to observation car, the Daylights were a sharp departure from the SP's normal dark olive passenger cars.
Leading the trains were the Southern Pacific's class GS (for "Golden State") Northerns, arguably among the handsomest steam engines ever built. Constructed by Lima Locomotive Works, inventor of the super-power concept, the Daylight 4-8-4s had the combination of power and speed that characterized steam power at its zenith. Class GS-4 engines, delivered in 1941 and 1942, were among the last and best-looking of the breed, with tall 80" drivers and enclosed all-weather cabs. In addition to handling premier passenger trains, the Golden State 4-8-4s were regularly used in high-speed freight service on the San Francisco-Los Angeles Overnight.