What do those strange-looking railroad signs represent along the Warrenton Branch?
Whistle Post 1
Sign located near Falmouth Street grade crossing (looking along trail toward direction of caboose).
  Whistle Post 2
Sign located near Madison Street grade crossing  (looking along trail toward direction of caboose).

By now you have noticed several strange-looking railroad signs appearing along the Warrenton Branch Greenway. The two styles of signs are examples of “whistle posts” (or “whistle boards”) formerly used by Southern Railway (now Norfolk Southern). These signs were purchased, restored and installed several years ago by volunteers of the Warrenton Caboose. The signs represent the whistle posts that once appeared along the Warrenton Branch where a public road crossed a railroad track (i.e., grade crossing). When a train locomotive approached a grade crossing, the whistle posts would alert the train engineer to sound a warning and alert vehicles (and horse-drawn buggies) of the approaching train. Up until the 1940s/1950s, the warning sounds were made by whistles from steam locomotives. After that, the warning sounds were made by air horns from diesel locomotives. The cast-iron signs that you see along the trail are authentic and quite old.

Dots and Dashes

The signs display a series of Morse code symbols. The symbols are either a dash (“___), which indicates a long blast of sound; or a dot (“o”), which indicates a short blast of sound. For example, the symbol sequence: “___ ___ o ___” would be heard as a “long blast, long blast, short blast, and long blast” as the locomotive approached a grade crossing.

There are two different pairs of vintage whistle posts that have been placed along the Warrenton Branch. One set of signs displays the sequence: “___  ___ o o” and the other set of signs displays the sequence:  “___ ___ o ___.” There is an interesting story as to why there are two different versions.

Prior to about the 1930s, the symbol sequence:  “___  ___ o o” was used on whistle posts (left photo above). An example of this can be seen on the pair of whistle posts located at the Falmouth Street grade crossing, approximately 4,800 feet down the Warrenton Branch from the caboose kiosk. This pair of cast-iron signs is dated around 1910. The sequence of sound blasts as required by these whistle posts seemed to work fine for warning the public at grade crossings - except for those occasional times when a train engineer was too quick to sound the last two short blasts from the locomotive before reaching the grade crossing. If the engineer finished sounding the whistle some distance before reaching the grade crossing, operators of horse-drawn wagons and noisy vehicles were not always adequately warned of the approaching train. Unfortunately, sometimes this occurrence resulted in a collision between the train and the public with grave consequences.

Recognizing the need to correct this problem, in the 1930s the railroad regulators revised the symbol sequence on the whistle post. The sequence was changed to read as follows: “___ ___ o ___” (right photo above).  An example of this sign can be seen on the pair of whistle posts located at the Madison Street grade crossing, approximately 2,700 feet from the caboose kiosk. This pair of aluminum signs is dated around the 1950s. With this small change in the symbol sequence, the train engineer now was required to continue to sound the last long blast while passing fully through the grade crossing. With this change, the public would assuredly hear the last long blast of sound and be well warned at the grade crossing of the approaching train. As a result, accidents between trains and the public were noticeably reduced. Since the change in the 1930s, the sequence for warning sounds for approaching grade crossings has remained unchanged: two long, one short, and one long.

Modern Whistle PostToday, whistle posts with Morse code symbols are no longer used. Instead, the signs display only a large “W” indicating where along the track the warning sounds from the locomotive should begin. Examples of several W-marked whistle signs can be seen when volunteers open the Warrenton caboose for the public to visit.

So enjoy walking the trail where once there were slow moving trains and sounds of loud whistles or horns at grade crossings. And when you walk by the whistle posts, you will know the story behind those strange-looking signs.

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Additional Information about Whistle Posts