Central Pacific Railroad mail car model

This model has a window and door arrangement similar to an 1870s Railway Post Office (RPO) car, but it may not accurately reflect route agent or RPO equipment used on the Central Pacific. A known plan from the Central Pacific depicts a mail car with a walkway from end-to-end along a recessed outside wall and without end doors. Such an arrangement allowed the train’s crew to move past the car without entering it. End doors on open-platform cars posed a security risk, since a would-be robber could attempt forcible entry into the postal car from a concealed position.

The Central Pacific Railroad was incorporated in 1861 and existed with that name until it was leased to the Southern Pacific Railroad in 1885. Mail was handled on the line in the custody of Post Office employees called "Route Agents" prior to 1877.

U.S. Railway Post Offices were established in 1864, five years before completion of the first transcontinental railroad between Omaha, Nebraska, and Sacramento, California. The Union Pacific and Central Pacific routes formed the line between those cities. RPO routes did not begin operating on the transcontinental route until the 1870s.