Data Trails: “The Power of Trees” (1855)

This post is part of a blog series on historical data vis titled “Data Trails. Snapshots from the history of data visualisation” and originally appeared over at my friends’ from Idalab, a Berlin-based specialist on data science and machine learning. 

Once we have grown used to a new technology, it is hard to turn back and imagine what it was like when it was all new and unheard of. We do not even have an idea of what it was like before the internet anymore. Likewise, the inception of the railways in the mid-19th century must have been a mind-blowing change process for its contemporaries. The new technology shot up the volume and speed of passenger and freight traffic overland to unprecedented heights within just very few years.

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New York and Erie Railroad diagram, 1855

This beauty of a diagram is considered to be the first organisational chart ever. It was drawn in 1855 and shows the structure of the New York and Erie Railroad Company, a large business of 4,715 employees which operated five railway lines with some 500 miles of tracks at the time. The company is envisioned as a magnificent tree, with its roots forming the center of power in the person of the president and the surrounding board of directors.

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New York and Erie Railroad diagram, 1855, Detail

From the president, the tree branches out to display six general officers and their teams, as well as the General Superintendent. From this latter, the company’s organisational structure unfolds growing „sky high“ in numerous elegant branches. Stylised round leaves serve to encode one employee each. It is alluring how the graphic oscillates between its floral, even poetic appeal and its somewhat – let’s say – practical contents. The whole chart displays an admirable swinging symmetry – someone really wanted to make this look pretty. But why would a railway company need such an elaborate org chart in the first place?

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New York and Erie Railroad diagram, 1855, Detail

Managing traffic on the new railway lines proved to be a complex task. Tracks were one sided with only so many passing places along the route. In the early days, traffic was controlled using a time interval system – meaning that sometimes a train would have to wait for hours (!) until an oncoming train had passed. In the early 1850s, two managers of the New York and Erie Railroad Company, Charles Milton and his successor Daniel McCallum pursued to use the new electrical telegraph along the railway lines to dispatch trains.

Telegraph offices were built at several crucial stations along the routes. These were thus able to communicate in real time with other stations along the line and transfer timely orders for trains to pass or wait. At first it seemed a dangerous idea to have the stations communicate with each other independently, as it dispensed with the time interval system which had worked as a buffer to prevent trains from running into each other. But the real time communication very soon proved to be working efficiently to cut delay times – as long as the chain of commands was crystal clear to everyone involved. Which takes us back to our diagram.

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New York and Erie Railroad diagram, 1855, Detail

What do you do when having to manage an organisation of unprecedented complexity, with people communicating in real-time, trying to avoid the risk of deadly accidents? Superintendent Daniel McCallum decided to outsource some traffic related decision-making to the local station managers, as only they knew the current situation on the route. But he had to make sure they only talked to the right people in the process.

It is fascinating to see how Mr. McCallum took to drawing a visual aid to help his employees operate errorless on their individual positions. The explanation note on the lower right explicitly discusses who can talk to whom – which is always and only the person succeeding or preceding an employee in the hierarchy drawn here. Unfortunately we have no evidence of whether and how the chart was used in the company’s offices, but there is no doubt that it is visually compelling enough to make people remember what they needed to know regarding their daily work flow. 

For more information on the New York and Erie Railroad and their early use of the telegraph look here and here. Images via Library of Congress. Someone took the effort to photoshop this scan in order to hide those ripped margins. You’ll find that file on Wikimedia. If you developed more appetite for tree diagrams, I recommend the excellent „Book of Trees“ by Manuel Lima, published by Princeton Architectural Press.