In the course of "treasure hunting" once often comes across interesting non-metal artifacts. Researching the history of these artifacts and how they came to be where they were found can be both fun and frustrating.
Marbles or ball-shaped objects found near railroad operations:
Processed taconite ore (starting after 1946)
Fiberglass marbles (starting after 1938)
Cleaning/processing marbles (possibly as early as 1910)
Cullet or raw glass for manufacturing
and probably not any marbles used for moving heavy freight
One might also run across a clay or glass toy marble at a railroad site, but this discussion focuses on industrial type uses.
Often found near railroad beds are rough rusty-brown spheres of taconite or "iron" ore. These aren't really marbles, but I'll mention them here just to prevent any confusion. Taconite is a mineral containing about 25-30% iron in the form of magnetite. It was not a profitable source of iron until after World War II, and in the 1950s a process was devised that made it more commercially viable. In this process, the taconite is pulverized and the magnetite is separated by magnets. This iron powder is then combined with clay and limestone to form pellets containing 65% iron. These pellets are commonly conveyed by rail, and are lost through accidents or poor handling along railroad tracks.
Ferrara's "Railroad Marbles" or Fiberglass Marbles
Glass marbles are also found along railroad tracks. The most common of these are 3/4" clear or greenish spheres often with characteristic wrinkles or indentations on the surface. These marbles are used in a process developed in the 1930s to manufacture fiberglass.
An oft cited story appears on the railroadiana.org website about railroad marbles. The article is attributed to Sam Ferrara, with the information first published in the Key, Lock & Lantern, Issue 87, Spring 1988. Unfortunately this story has no sources cited and is probably more fiction than fact. All online references seem to point back solely to Ferrara's article, with no secondary sources available.
Ferrara says that marbles were first used circa 1885 as rollers to move heavy freight in depots and warehouses. This would not explain why marbles are found in large quantities along tracks far from any depot or warehouse.
Ferrara says that between 1885 and 1890, the Wheeling Glassworks was commissioned to make glass marble that would support 500 pounds of weight. At that time, clay marbles were the most common form of marbles in the United States. They became even more common after Akron, Ohio resident Samuel Dyke invented a machine patented in 1890 that allowed his company to produce one million clay marbles per day, equal to five boxcars of marbles. Glass marbles were still then relatively costly, being hand manufactured in a time-consuming process. This changed in 1905, when Akron resident Martin Christensen patented his automated glass marble machine and founded a company bearing his name that manufactured over 12 million glass marbles per year.
Ferrara's story states that "marbles were purchased by the tons," which seems unlikely as glass marbles would have still been handmade and expensive before 1905. Steel roller bearings would have probably been cheaper and more readily available to use for this application. Most contemporaneous reports indicate that railroad freight was moved with human power and wheeled dollies rather than marbles.
Searches of railroad related literature of the period does not turn up any mentions of using glass marbles as roller bearings to move freight.
The marbles depicted and described in the railroadiana article as 3/4" greenish-clear glass with air bubbles visible and "linear indentations from straw or forming" appear to not be a product of the 1880s, but the fiberglass marbles of the 1930s.
In 1938 Owens-Corning Fiberglas Corporation was created to mass-produce glass fibers for insulation. Their first manufacturing plant was established in Newark, Ohio. Marbles are used in this process because they can be added to the glass melt at a controlled rate, keeping the temperature constant, and the clear marbles can be inspected for impurities. The melted glass is then extruded to form the hairlike glass fibers. Online message board posters report finding these marbles along the track leading to the Johns-Manville fiberglass plant in Corona, California, and that they were shipped from the Johns-Manville plant in Cleburne, Texas. However one poster mentions that these marbles were 1.5" in diameter. Another poster online said there used to be a lot of glass marbles shipped to the Johns-Manville plant in McPherson, Kansas and that there would be piles of them in the switchyard at Newton, Kansas.
Several eBay sellers use Ferrara's story to sell modern fiberglass marbles to the gullible as the circa 1885 freight moving devices. Other sellers are also representing these fiberglass marbles as the "cat's eyes" used in vintage reflective signs.
Cullet, Raw, or Recycled Glass
Glass marbles might also be used as cullet in the manufacture of glass objects, though there is little documentation seen referencing marbles being used for this purpose. Cullet is recycled broken or waste glass used in making new glass. The marbles could be recycled glass formed into marbles to be used in a manner similar to the fiberglass process to add recycled material to new in measured quantities at a controlled rate.
One post to an online forum reported that clear green marbles were common in Toledo (Rossford), Ohio. Libbey Owens Ford (LOF) "used to have mounds of them at their factory. They were shipped in by train or boat." LOF was a producer of plate and automotive glass. Another online message board says that LOF made industrial glass marbles from the 1940s through the 1970s.
Cleaning or Processing Marbles
Ferrara says that the Pennsylvania Sand Company used large 2" diameter marbles in the bottom of hopper cars to "help the flow of sand when emptying." There are no sources cited and no photographs of these marbles. Other online message boards list that marbles were used for this purpose (to increase the flow of powdered or fine granulated material). The marbles used in this way could theoretically be easily screened out when a hopper car was emptied. Others say that marbles were used to clean hopper or tanker cars, as powdered substances would have a tendency to compact on the bottom and clump or stick to the walls and crevices in the cars. SurflinerHogger on trainorders.com said, "Back in the 80's I was told by a worker at the cement plant in Victorville they (marbles) were also used to clean some cement cars by shaking loose extremely fine residue found in cars loaded with trona and other fine materials used in the making of cement. He said they would fall down out of the cars and get ground up in the auger with the other product during the unloading process. They were all over the place near the unloading grate."
I discovered some different multicolored glass marbles at a disused railroad siding next to the site of a circa 1912-1980 chemical and fertilizer plant. This was the only known business on the site. These marbles were different common glass colors, cobalt, clear, light olive green and aqua. No dark green or brown glass marbles were found. These marbles all have a heavily frosted appearance, like sea or beach glass. Since the chemical plant would have dealt with hopper cars of powdered substances, perhaps these marbles were used to clean or aid in the flow of those materials from the cars. The frosted appearance would have come from some sort of abrasive use of these marbles. Judging by the colors of the glass used in the marbles found at this site, they seem to be from circa 1900-1930, and while the clear marbles have a slight pinkish cast, there were none of a purple/amethyst tint which would indicate that they were made from pre-1915 glass with manganese content. My best guess is that these marbles were probably used in the hopper cars to assist in the unloading (or cleaning out) of material at the fertilizer plant between circa 1915-1930.
Locations where marbles have been noted/found:
Along RR tracks Columbus, OH
Along right of way of Santa Fe outside of Lamy, NM
The diamond in Wellington, OH
WLE route from Huron, OH
Near rail yard Barstow, CA
Along Santa Fe from KS to CO
Fiberglass plant at Winders, GA
Cumberland Branch of B&O
Along right of way Ludlow, CA
Oro Grande, CA
RR tracks in Riverside, CA
On tracks near Williamstown, WV
B&O RR grade near Greenfield, OH
B&O RR line near Hamden, OH
Near fiberglass plant at Huntingdon, PA
CNJ Southern Division, South Jersey, NJ
Texas & Pacific near Arlington, TX
PRR East-West mainline, Chester County, PA
Sidings near coal tipples at Philipsburg/Morrisdale, PA
RR tracks near Hershey, PA
RR tracks at Wiemar, CA
Walking active railroad tracks is dangerous. Railroads take a dim view of trespassing as well as theft of any railroad property.