When Was the Semaphore Arm First Used in the US?

NW Mailing List nw-mailing-list at nwhs.org
Wed Mar 21 16:29:11 EDT 2012

For decades I have thought about this question:  When and for what purpose was  a semaphore arm first used on the N&W?  Having read all the reports and documents I can find from the XIXth Century, there seems to be not even a hint at an answer.  Therefore, I expanded the question a bit and put together the following little musing, asking when the first semaphore arm might have been used in the United States, and sent it out to some others who debate arcane old topics.   I hope you do not consider the piece "off topic " for the N&W List, as N&W history was certainly forged in the context of what was going on elsewhere in the industr y.

-- abram burnett

I am searching for another needle in a haystack... When and where was the first use of a semaphore signal arm in the United States?


ASSUMPTIONS. The assumption is that there would have been no need for a semaphore arm unless one of the following three activities was being done: (1) Delivering Train Orders (first Train Order was 1851.) (2) Blocking Trains (first done in the US in 1865, but Banner Box Signals were used for this purpose.) (3) Protecting an interlocking (the first interlocking in the US was in 1870.)


Here's what we know of the early history IN ENGLAND, from which most of our signal practices derive:


1. Invention of the semaphore arm is credited to Charles Hutton Gregory in the year 1843. In that year, Gregory made the first attempt to concentrate the operation of switches and signals at one place, and used semaphore arms for signals, but in his system the levers were not interlocked. The location was Bricklayers' Arms Junction, south of London.


2. In 1851, Austin Chambers did the first real "interlocking" of switches and signals, on the North London Railway. (I'm looking for information on this installation...)  No doubt, he followed the practice of his fellow Brit, Gregory, in using semaphore arms as signals.


3. In 1856, John Saxby received a patent for "a mode of working simultaneously the points and signals of railways at junctions," and apparently shortly thereafter installed his new "interlocking" machine... also at Bricklayers' Arms.  Drawings seem to indicate that Saxby used Gregory's semaphore arms.


IN THE UNITED STATES, here are some significant dates.


1. In 1851, the first Train Order was issued on September 21, at Harriman, NY, on the New York & Erie RR.


2. In 1865, Ashbel Welch installed the first Manual Block System between Trenton and Kensington (Philadelphia) on the Camden & Amboy RR, using Banner Box Signals. (In 1867, this system was extended on the New Jersey RR to Jersey City, NJ. In 1870 it was extended westward to Mantua Jct (present Zoo) in Philadelphia. By 1876, the PRR Main Line east of Pittsburgh was equipped with Welch's Banner Box Signals.)


3. In 1870, William Robinson installed the first track circuit (open-circuit principle) at Kinzua, Pa, and used an electromagnetic disc-type signal. In 1872, Robinson changed the arrangement of the track circuit to the closed-circuit principle, which is still in use today.


4. On December 7, 1870, the first interlocking was installed in the US, a British Saxby & Farmer machine at Top of the Hill Jct, Trenton, NJ, on the Philadelphia & Trenton RR.  Without doubt the semaphore arm, which had been used since 1843 in England, was used.


5 In 1874, the first US-made interlocking machine was installed by John M. Toucey & William Buchanan at Spuytin Duyvil, NY, 15 miles north of New York City, on the Hudson River RR, replacing a previous British interlocking machine about which I have found no information.


6. Written accounts indicate that, at the time of the completion of the Transcontinental Railroad in the US (1866,) semaphores were not in use on that road, and a red flag was stuck into a post to indicate that Train Orders were to be received.


TENTATIVE CONCLUSION: It appears to me that a date for the introduction of the semaphore arm in the US is probably bracket by two events:  (a) The 1851 implementation of the Train Order, and (b) the 1870 installation of a Saxby & Farmer interlocking machine at Top of the Hill Jct in Trenton.  Prior to the 1851 implementation of the Train Order, there would have been no use for a semaphore arm in American railroad practice. But with the 1870 installation of a British interlocking at Top of the Hill Jct, New Jersey, the British semaphore arm, which had been in use for 27 years in England, without doubt came to America.




1. Following the "invention" of the Train Order in 1851, how did the New York & Erie RR indicate that Train Orders were to be received at a station? Was the "red flag in a post" used, a semaphore arm, or some other device? At what date did the NY&E begin using semaphore arms to indicate the delivery of Train Orders?


2. Was the semaphore arm being used in the US for any purpose prior to the 1870 installation of the British interlocking at Top of the Hill Jct?


3.  Did William Robinson, following his 1870/1872 invention of the track circuit, ever change from disc signals to semaphore arms?  During Robinson's 1876-1877-1878 installations on the Boston & Providence RR, the Old Colony RR, and the Boston Lowell & Nashua RR, what did he use for signals... discs or semaphore arms?  Are there surviving Robinson patents or items of advertising from this period, which might furnish an answer?


-- adb

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