Wigwag (railroad) - Design

Design

PE's earliest wigwags were gear-driven, but proved difficult to maintain. They were originally built in the railroad's shops. The final design, first installed at a busy crossing near Long Beach, California in 1914, utilized alternating electromagnets pulling on an iron armature. A red steel target disc, slightly less than two feet in diameter, serving as a pendulum was attached. A red light in the center of the target illuminated, and with each swing of the target a mechanical gong sounded.

The new model, combining sight, motion and sound was dubbed the Magnetic Flagman, with production by the Magnetic Signal Company of Los Angeles, though history is unclear as to exactly when the changeover to Magnetic Signal took place.

Three mechanically identical versions were produced: The upper-quadrant signal was mounted directly atop a steel pole and waved the target above the motor box. It was intended for use where space was limited. Since the target no longer served as the pendulum, a cast iron counterweight opposite the target was used. Accurate computer-generated animation of this type of signal can be seen in the 2006 theatrical release, Cars. The lower-quadrant version waved the target below the motor box and was intended to be above traffic on a pole mounted cantilever (see above photos). Some railroads, especially in the northwestern US, mounted their lower quadrant versions directly on top of a tall steel pole similar to the upper quadrant signal. They were placed on one side of the road or the other or on an island in the center of the road. They often had crossbucks fastened on top of the motor box. A lower quadrant signal of this kind is seen in the 2004 film Lemony Snicket's A Series of Unfortunate Events.

Though Magnetic Signal manufactured a steel pole and cast-iron base for this purpose (which served as a cabinet for backup batteries and relays), Pacific Electric often mounted the cantilevers on the wooden poles that supported the overhead catenary providing power for streetcars. This rendered batteries unnecessary, since failure of PE's generators resulted in a shutdown of the railway. This also permitted the relays to be housed in a separate inexpensive cabinet, reducing the cost of the installation.

The Magnetic Flagman wigwag waves its target with large, black electromagnets pulling against an iron armature. Contacts slide to switch current between the magnets. Each Magnetic Flagman includes a builder's plate (bottom center) detailing patent dates and power requirements.

The third and least common version was a pole mounted lower-quadrant signal suspended above an octagonal steel frame that surrounded the target, presumably to protect both banner and motor box from being damaged by passing vehicles. Dubbed the "peach basket" because of the protective framework, the apparatus was crowned by another visual warning, the traditional X-shaped "RAILROAD CROSSING" sign, or crossbucks. The majority of peach baskets were used by the Union Pacific Railroad. One version of this signal had the lower stripe on the banner replaced with the word stop that was lighted. When the signals was at rest, the words were hidden behind a screen that was painted to look like the missing stripe. They were either mounted on an island in the center of the road or on the side of the road.

There were a few different models that were either manufactured by Magnetic Signal or customized by the different railroads. A few examples included two signals on the same pole for different traffic approaches, a circular upper quadrant signal in which the target swung in a circular frame, and three-position signals where the target was hidden behind a sign when the signal was inactive. The Norfolk and Western decided to make a change where the motion-limiting bumpers were placed on the front of the signal instead of inside at the rear. They felt that torque on the armature was reduced. They also had unique lights on their banners.

Any version could be ordered to operate on the railroad signal standard of 8 volts DC (VDC) current or the 600 VDC used to power streetcars and electric locomotives, with little more than a change in the electromagnets. Most, if not all, of the 600 VDC units were used by PE. With the conversion to diesel power after PE sold its passenger operations in 1953, those 600 VDC wigwags were gradually converted to 8 VDC units. There were also some 110 volt AC model Magnetic Flagmen used on several railroads, including Norfolk and Western, Winston-Salem Southbound, and the Milwaukee Road. Since AC power did not generate good torque, a coil cutoff device was installed that utilized all four magnets until full motion of the banner was obtained, then 2 of the magnets went off line and movement was maintained by the remaining two magnets. Other options included a round, counterbalancing "sail" for use in windy areas and which were sometimes painted in the same scheme as the main target, a warning light with adjustable housing, a rare, adjustable turret-style mount for properly aiming the signal if space considerations did not allow for the cantilever to fully extend over the roadway and an "OUT OF ORDER" warning sign that dropped into view if power to the signal was interrupted. The last known example of the turret-mounted wigwag was removed from service in Gardena, California in 2000, while the versions with the warning signs were mostly shipped to Australia. One surviving example is on display at a railway museum in Victoria, in addition to one which has been restored and now operates on the Puffing Billy Railway. An example or two of each signal still survive with collectors.

After these distinctive signals were installed train-versus-car collisions began decreasing at PE grade crossings. They were so common throughout the area that they became near-icons of Southern California motoring. They became popular and Magnetic Signal wigwags began appearing at railroad crossings across the United States (including Alaska on the Copper River & Northwestern Railroad and several Hawaiian railroads), Canada, Mexico, and as far away as Australia. There are also photographs of Magnetic Flagmen in use in Europe.

A ruling by the United States' Federal Railroad Administration (FRA) mandated a change in the target in the early 1930s, necessitating a change in the paint scheme from solid red to a black cross and border on a white background, but remained otherwise unchanged until another FRA ruling that changed the standard to the alternating red light system in use today. The "black cross on a white background symbol" was adopted for use in the US as the traffic sign warning drivers of an upcoming grade crossing and, in modified form with a yellow background and the cross rotated 45 degrees into an "X," remains in use today. It was also incorporated into the corporate logo of the Santa Fe Railroad. Some railroads, among them the Louisville and Nashville Railroad, instead used a concentric black circle on a white background, resembling a bullseye. This scheme was rare, partly because the L&N used few wigwags.

This, along with other rules pertaining to grade crossing signaling that the wigwag was unable to meet due to its power requirements, rendered it obsolete for new installations in 1949, but grandfathering laws allowed them to remain until upgrades to the crossings they protected were necessary. Magnetic Signal was sold to the Griswold Signal Company of Minneapolis shortly after WWII. Production of new signals continued until 1949, and replacement parts until 1960.