This is the HO Scale SP Coast Daylight Train #99 Articulated Chair Car - Southern Pacific #W2458/M2457 from Broadway Limited Imports.
Imagine seeing the beautiful Southern Pacific GS-4 pulling a string of those magnificently painted passenger cars along the California coast. Then add the sight of a Cab Forward applying her muscle for the climb over the steep grade between San Luis Obispo and Santa Margarita. Any railfan's delight.
The Morning Daylight was two separate trains, #98 and #99. Each operated as a unit train and cars were not normally added or removed, but for extra capacity, chair car pairs were added. The two trains left San Francisco and Los Angeles at 8am, passed each other in the neighborhood of San Luis Obispo, and arrived around 6pm.