The Mail Car

Museum's RPO car has a 60' (foot) mail compartment, so there would be 6 to 10 men working.  This depended on the season though; with Christmas being the busiest. 

As the RPO cars were hauled (mostly) on passenger trains, the mail transit time was directly proportional to how fast these trains were.   The US passenger trains were the fastest in the year 1957, when 77,460 route miles (35% of the total) had average speeds over 65 mph, and 10% of the route miles had average speeds over 70 mph.  Note, these are the average speeds, so tops speeds were considerably higher; sometimes over 100 mph.   See the FAQ: "Why doesn't the US have fast trains" in the "Fast Trains" page for why 1957 was the fastest year.   Below, is an example of the elapsed time, for various years, for the fastest train between Chicago - Oakland (2260 miles), and Chicago - New York (960 miles), a total distance of 3,220.   Note that, no single train ran the entire distance; the mail would be transferred between trains in Chicago.  The transfer time would be a few hours.

Times from Chicago to:
  Oakland   New York     Total
Year   hours/days hours/days hours/days
1910   83    / ~3.5     24  / 1 107  / ~4.5
1921   69    /~3     21 / .9             90  / ~3.75
1939   58    / ~2.5     16 / .66     74  / ~3.2
1950   39    / ~1.6     16 / .66     55  / ~2.33

1950 was about the fastest that this route combination ever got.  Not counting the transfer time, the average speed for the 3,200 mile coast-to-coast trip was about 58 mph; pretty good for letter.  Add a day for local handling on either end plus the transfer time, and that's (very roughly) how long it would take.  It should be noted that the New York City - Chicago RPO route was the nation's busiest at this time, as New York City and Chicago were the 1st and 2nd most important areas of the country.  New York City was the financial center of the nation (like today), and the Chicago area was the largest manufacturing center of the nation.  It was said that during WW2, the Chicago area produced 10% of the entire nation's GDP.   The New York Central Railroad, which operated the New York - Chicago RPO route, ran many mail-train each day between these two cities.  

What follows is a very very simplified description of how a 1st Class letter got from one city to another on an RPO car.  

 Let's say, it’s May of 1945 (before the Museum's RPO car was put into service), and a letter is mailed in Seattle and addressed to Podunk Iowa. A clerk in the Seattle Post Office would look at the letter and determine if the address was for Seattle.  If so, it could be dealt with locally.   But our letter is for Iowa, so the next determination would be: which RPO Car the letter has to go on so it can reach its final destination.   In Seattle, there are 3 RPO Car routes the letter could go on:  north towards Bellingham (and Canada); south towards Tacoma, Olympia, and Portland; and east toward Spokane and beyond.  Our letter is going east.  The Iowa letter is put into a large mail bag, along with other letters going east; some only going as far as (say) Spokane WA, and thousands of others going to (pretty much) every state south of and east of St. Paul MN.  The eastbound RPO Car leaves Seattle at 9:30pm, and is part of the consist of the Great Northern Railroad's Empire Builder train.  Prior to departure, the car will be loaded with bags of unsorted mail from Seattle, as well as mail from any connecting RPO's from the north (Bellingham and Canada).  As the car itself came from Tacoma, it's already loaded with unsorted bags of mail from there, as well as mail from any connecting RPO's from the south (Portland).  When the train leaves, the sorting starts.   Clerks take an unsorted bag, unload it on the table, and start looking at each letter to determine which pigeon-hole the letter goes in.   There are more than 700 pigeon-holes in a 60' (foot) RPO compartment.   Each pigeon-hole is labeled with a destination name.   The destination names can be: 1) Post Offices serviced specifically by this RPO Car; 2) RPO lines that connect with this RPO Car (e.g., various RPO's connecting at St Paul, a single RPO connection at Shelby MT for Great Falls and Billings, and others); 3) "large cities" not serviced by this RPO Car but which are the destination point of many letters (e.g., New York City, Washington DC, Detroit); 4) States, 5) special destinations (e.g., foreign countries, "The White House", "Santa Clause", etc...).   Eventually, a clerk will pick up our letter and read: Podunk Iowa.  Let's say our clerk never heard of Podunk Iowa, so he would yell-out the name and - most likely - one of the other clerks, perhaps with 20+ years of experience - who has 10,000+ destinations memorized, would recognize it, and he'd yell back (something like):  "Minny-in-Casey", and the clerk who asked would flip the letter into the pigeon-hole labeled: "MSPL & KC" (Minneapolis and Kansas City".   When the "MSPL & KC" pigeon-hole fills up, the letters are taken out, bound with twine, tagged with a "MSPL & KC" routing slip, and the entire bundle of letters thrown into a large bag labeled (something like): "MSPL & KC, TR 17”.   

The RPO crew which got on the car in Tacoma will get off in Spokane WA (after 12 hours), and another crew will get on for another 8-12 hours of sorting.   The Empire Builder arrives in St. Paul at 10:30 pm, 47 hours after leaving Seattle.  The "MSPL & KC, TR 17" bags, along with bags for every other connecting RPO line at St. Paul, as well as bags with mail for the city of St. Paul, are unloaded.   All the bags labeled “MSPL & KC, TR 17” – one of which contains our letter – are transferred to the RPO Car of Rock Island Train #17, the overnight train to Kansas City, which originated in Minneapolis.    When the train departs, at 11:25 pm, the RPO crew starts sorting mail again.   Eventually, the bag containing our letter is worked, and the clerk reads: “Podunk Iowa” on our letter.  He recognized this immediately, as this is a town on his RPO line; he’s sorted countless letters to Podunk.  He flips the envelope into the pigeon-hole specifically labeled “Podunk Iowa”.   As the train speeds south and a few miles from Podunk, the clerk clears the letters from the Podunk pigeon-hole, puts them into a mail bag, seals the bag, and walks to the door of the RPO that has the mail-hook.  It’s dark, about 2:20 am.  By experience, he feels the train curve to the right; he's about 2 miles from Podunk now…  He opens the door: it's raining, but not too bad…  There's the engineer’s signal, one long whistle: the Podunk mail-crane is less than a mile away, time to put on the goggles…  He waits for the bridge over Podunk Creek: 30 seconds now…  The dim lightbulb on the mail crane, barely visible in the rain, looms into view as the train approaches at about 40 mph… He raises the mail-hook with his right arm, kicks off the mail bag for Podunk, the mail-hook snags the new southbound Podunk mail bag off the mail-crane, he pulls the bag in, lets go of the mail hook, and tosses the bag to the pouch-man, more mail to sort…   By mid-morning, the Podunk mailman has delivered our letter.  Total time, about 3 days.

By the 1920's there was a highly efficient, competitive, flat-top-road system being financed, built, and maintained by various agencies at all levels of government: Federal, State, County, and Municipal.   This effectively rendered about half of the private railroad network commercially unviable.  As trucks took over short distance freight service, rail traffic declined, which meant the frequency and speeds of trains declined (as profits declined), which causing the Post Office to seek alternatives to the RPO lines affected.   After the Federal Government began building the Interstate Highways in the late 1950's, trucking took over more and more freight service, which caused the railroads to reduce speeds and service on its long-distance routes too.  By 1962, only 262 RPO routes were still operating.  In September 1967, the Post Office canceled all mail by rail contracts.   

The railroad's death spiral didn't end until the late 1970's when the US government deregulated the railroads and eliminated the ICC.  See the FAQ: "Why doesn't the US have fast trains" in the "Fast Trains" page. 

Eventually, the railroads lost most time-sensitive transportation; with perishables, mail, and package express being the some of the most profitable ones.  However, mail and packages still ride the rails in container trains.