Herman Haupt's Potomac "Carfloat"

[John Hartwell]

In another thread, @JPK Huson 1863 posts this photo, asking "RR cars on barges! How did they do that?"

The key to the answer is in the rails on the pier to the left. The barge, which has corresponding sets of rails attached to its deck, is carefully docked and locked in place so that the sets of rails match precisely.
Cars can then be rolled across, from pier to barge.

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This is an early example of "car float" technology, used to transfer train cars to barges or ferries. More modern examples generally arrange the cars lengthwise, rather than transversely, as Haupt's Civil War example did.

This video shows how the modern operation works.

Trainweb sketches Haupt's carfloat:

The first intensive use of the dedicated carfloating of freight in the United States seems to have occurred during the Civil War, when freight cars were floated on makeshift barges along the Potomac River, to serve places where existing rail lines could not reach for various reasons. As published in 'American Railroad Freight Car', by John H. White, Jr. (1993, Johns Hopkins University Press) credits Brigadier General Herman Haupt for first carfloating on a barge in 1862, during the Civil War. In the October 2000 issue of "Model Railroader" magazine, p. 82-85 there is an illustrated article on the November 1862 construction, under the direction of Brigadier General Herman Haupt, of a carfloat operation for the Union Army at Alexandria, Virginia.​

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Haupt had been the Chief Engineer of the Pennsylvania Railroad and was in the process of constructing the Hoosac Tunnel when he was "conscripted" to run the U. S. Military Railroad. Two steamtug drawn floats were constructed, each holding 8 cars transversely, and they were served by triple-track aprons at the transfer landings, running from Alexandria, Virginia, down the Potomac River 60 miles to Aquia Landing, about 10 miles northeast of Fredericksburg, Maryland.​

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In addition, George Abdill on page 48 of his book "Civil War Railroads: A Pictorial Story of the War between the States, 1861-1865 "(1961, Indiana University Press) calls it "pioneer car ferry" which it was not. Instead, it was the pioneer carfloat in the United States.​

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General Haupt supervised the construction of these transfer bridges at both terminals of this proposed water route. General Haupt also designed, requisitioned materials and built the unique railroad float barges. The carfloats consisted of two large-sized Schuylkill type barges moored side by side, across both of which long timbers were placed supporting eight tracks mounted transversely (from port to starboard instead of the modern configuration of bow to stern).​

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At Alexandria, VA; the loaded freightcars were placed singly aboard each of the eight tracks of the carfloat. The carfloat was then towed sixty miles by steam tug to Aquia Landing, VA. Once at this location, railroad crews unloaded the carfloats by pulling the cars.​

It's an interesting operation that deserves further study.

 

[John Hartwell]

Here's a modern model reconstruction of the Transer Bridge at Aquia Landing:

This and several other original and reconstruction illustrations from the Dec. 10, 2017, edition of the excellent model railroading blog "U.S. Military Railroads"

 

[wausaubob]

You know what they say about necessity and invention!