Post Office routes, Air Mail Facility, terminal railway post offices, and transfer offices, were shifted to the Bureau of Transportation. Decline and withdrawal At their height, RPO cars were used on over 9,000 train routes covering more than 200,000 route miles in North America. While the majority of this service consisted of one or more cars at the head end of passenger trains, many railways operated solid mail trains between major cities; these solid mail trains would often carry 300 tons of mail daily. After 1948, the railway post office network began its decline although it remained the principal intercity mail transportation and distribution function within the Post Office Department (POD). There were 794 RPO lines operating over 161,000 miles of railroad in that year. Only 262 RPO routes were still operating by January 1, 1962. In 1942, the POD began experimenting with a highway version of the RPO to serve the same purposes along routes where passenger train service was not available. These highway post office (HPO) vehicles were initially intended to supplement RPO service, but in the 1950s and 1960s, HPOs often replaced railway post office cars after passenger train service was discontinued. The last interurban RPO service was operated by Pacific Electric Railway on its route between Los Angeles and San Bernardino, California. When the post office made a controversial policy change to process mail in large regional "sectional centers," mail was now sorted by large machines, not by people, and the remaining railway post office routes, along with all highway post office routes, were phased out of service. In September 1967 the POD cancelled all "mail by rail" contracts, electing to move all first class mail via air and other classes by road (truck) transport. This announcement had a devastating effect on passenger train revenues; the Santa Fe, for example, lost $35 million (US) in annual business, and led directly to the ending of many passenger rail routes. After 113 years of railway post office operation, the last surviving railway post office running on rails between New York and Washington, D.C. was discontinued on June 30, 1977. The last route with a railway post office title was actually a boat run that lasted a year longer. This boat railway post office was the Lake Winnipesaukee RPO operating between The Weirs, New Hampshire, and Bear Island on Lake Winnipesaukee. The final date it operated with a postmark