Transorma Mail Sorting Machine Sign

Object Spotlight
Transorma Mail Sorting Machine sign

Transorma Mail Sorting Machine sign

photo of postal workers at the Transorma Semiautomatic Letter-Mail Sorter
Transorma Semiautomatic Letter-Mail Sorter
photo of Transorma Semiautomatic Letter-Mail Sorter
Transorma Semiautomatic Letter-Mail Sorter

One of the ongoing challenges of the Post Office Department over the course of the 20th century was sorting an ever-increasing mail volume. The Department took a step towards solving this problem on April 10, 1957, with the installation of the first semiautomatic sorting machine at the Blair Post Office in Silver Spring, Maryland.

Standing thirteen feet high, the Transorma Letter Sorting Machine consisted of upper and lower sections separated by a platform that surrounded the entire machine. A conveyor belt transported mail from the lower level to one of five operators sitting in front of sorting keyboards on the upper level. The operators read the destination and keyed a sorting code. The letter was then automatically transferred to a letter tray and deposited into one of 300 chutes that returned the mail neatly stacked to the lower level. At full operation with five keyboard operators, the Transorma could sort 15,000 letters per hour, double the amount that the same number of clerks could do by hand.

photo of men at mail sorting machines
Men at mail sorting machines

The Transorma was manufactured by the Dutch company Werkspoor and distributed in the United States by Pitney-Bowes. The name of the machine comes from combing the words Transportation and Sorting with the first initials of the machine’s Dutch inventors, Marchand and Andriesen.

The Transorma proved the potential for expediting mail processing at a reduced cost, but it also showed the limitations of semi-automatic machinery. Today Optical Character Readers automatically sort the vast majority of the letters in the U.S. mail stream without any human interaction.

A public art installation titled Transorma/Transforma now stands on the site of the former Blair Post Office. Large stainless steel gazing balls mark a winding path through an outdoor arcade that suggest the modern machine parts of the first semiautomatic mail sorting in the United States.

A Collecting Note:

A synecdoche is a figure of speech that substitutes a part for the whole, such as using "hand" for worker or "wheels" for car. Museums frequently use a variation of this rhetorical device in their collecting practices. When it is impractical to collect an entire artifact due to space constraints, museums may collect only a part of the larger artifact. In the case of the Transorma, the 15-ton machine was too large to fit in the National Postal Museum's galleries, so curators collected two signs. The signs are a starting point – supplemented by photographs, oral histories, and other artifacts – to tell the story of postal automation.

Transorma Mail Sorting Machine sign
Transorma sign


  • Operation and Maintenance Manual: TRANSORMA Letter Sorting Machine.Pitney-Bowes and Werkspoor. Stamford, Connecticut.
  • The Postmaster General reports on the services of the United States Post Office Department during Fiscal Year 1957.

For further reading

Moving the Mail

By Allison Marsh

Additional Imagery

Transorma patent diagram
Transorma patent
Transorma patent diagram
Transorma patent