Rock Types

Yard Ballast

Track ballast/Yard Ballast It is another essential part of railroad infrastructure, although it may just look like plain ole gravel. This stone plays a vital role in acting as a support base for the railroad ties and rails. Yard ballast allows for proper drainage of water away from the track. That is why the stone is always sloped downward and away from the railroad.

You may be wondering how such a term came to define the stone which supports the railroad track structure. Interestingly, it has its roots dating back to early times when the stone was used as ballasting for sailing ships.  In today’s railroad industry the use of ballast, its application, and purpose has changed little since it was first employed. It will likely always remain an important component as a part of the track structure.


In new construction or for repair work, the tracks are ballasted to yard/industrial standards. Ballast less depth than mainline, since speeds will below.  The spaces between ties are filled in with smaller gravel to tie-top level to provide better footing for yard workers.  French drains are often installed, and there may be a manhole or two where the drain lines trunk together.

Track ballast (Yard Ballast), as it is known. It is another essential part of railroad infrastructure, although it may just look like plain ole gravel.
Track ballast (Yard Ballast), as it is known. It is another essential part of railroad infrastructure, although it may just look like plain ole gravel.

Years of use

Over time, the ballast gets fouled with spilled lading and blown-in dirt.  Weeds begin to grow.  During the transition era and earlier, journal box drippings would slowly saturate the ground (poor man’s tarmac.)  Cinders from would be spread in the yard. Well maintained yards will be kept pretty clear of foliage and will occasionally get a ballast transfusion where needed.  Unmaintained yards will gradually change to muddy quagmires, sometimes with tracks submerged below the railheads in glop.  Tall weeds and bushes abound, and even an occasional sapling if the tracks are embargoed.


An interesting effect to model is to model the entire yard somewhat grimy with some weed growth. Onther is to make turnout with fresh, clean ballast.

Most (if not all) prototype yards had something keeping the tracks in place.  Cinders were common during the steam and early diesel era. As was “regular” ballast when major yards were built/rebuilt over the years.  Over time, dirt, soil, grease, grime, gets everywhere. Also make some spots looking as if there has never be ballast to begin with.

Of course, while crushed cinder with basalt is the aggregate of choice for today’s railroads. In years past everything from slag to cinders has been used (always resourceful years ago railroads would use whatever they could find). Some light density railroad lines would appear jet black cinders were used to ballast the route. In any event, track ballast must regularly be cleaned or added as when dirt and grime build-up. When this happens within the rock it reduces its ability to properly drain water. 

The ballast also acts as a support base for the railroad track structure giving it strength and rigidity but also allowing for flexibility when trains pass over. Black cinder with basalt is often most used as ballasting.ballasting. It is a hard stone that will lock together providing for extra strength.


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Rock Types

Granite Ballast

Granite aggregate is often chosen as the granite ballast used to support the rails in railway construction. Also with roadbuilding, granite aggregate is popular with track layers. Due to its strength, durability, and excellent drainage-promoting qualities


Granite is a light-colored igneous rock with grains large enough to be visible with the unaided eye. Slow crystallization of magma below the Earth’s surface is how granite forms. Granite is composed mainly of quartz and feldspar with minor amounts of mica, amphiboles, and other minerals. This mineral composition usually gives granite a red, pink, gray, or white color with dark mineral grains visible throughout the rock. Granite is also well known for its many world-famous natural exposures. These include Stone Mountain, Georgia; Yosemite Valley, California; Mount Rushmore, South Dakota; Pike’s Peak, Colorado; and White Mountains, New Hampshire.

Granite is the best-known igneous rock. Many people recognize granite because it is the most common igneous rock found at Earth’s surface. Granite is used to making many objects that we encounter in daily life. These include countertops, floor tiles, paving stone, curbing, stair treads, building veneer, and cemetery monuments. Granite is used all around us – especially if you live in a city.


Granite is the rock most often quarried as a “dimension stone” (a natural rock material that has been cut into blocks or slabs of specific length, width, and thickness). Granite is hard enough to resist abrasion, strong enough to bear significant weight, inert enough to resist weathering, and it accepts a brilliant polish. These characteristics make it a very desirable and useful dimension stone.

Granite has been used for thousands of years in both interior and exterior applications. Rough-cut and polished granite is used in buildings, bridges, paving, monuments, and many other exterior projects. Indoors, polished granite slabs and tiles are used in countertops, tile floors, stair treads, and many other practical and decorative features.

Granite is also used as crushed stone or aggregate. In this form, it is used as a base material at construction sites, as an aggregate in road construction, railroad ballast, foundations, and anywhere that crushed stone is useful as fill.


  • Engineering: Engineers have traditionally used polished granite surface plates to establish a plane of reference, since they are relatively impervious, inflexible, and maintain good dimensional stability. Granite tables are used extensively as bases or even as the entire structural body of optical instruments, CMMs, and very high precision CNC machines because of granite’s rigidity, high dimensional stability, and excellent vibration characteristics.
  • Building: granite has been extensively used as a dimension stone and as flooring tiles in public and commercial buildings and monuments. Aberdeen in Scotland, which is constructed principally from local granite, is known as “The Granite City”. Because of its abundance in New England, granite was commonly used to build foundations for homes there. The Granite Railway, America’s first railroad, was built to haul granite from the quarries in Quincy, Massachusetts, to the Neponset River in the 1820s.
  • Sculpture: In some areas, granite is used for gravestones and memorials. Granite is a hard stone and requires skill to carve by hand. Until the early 18th century, in the Western world, granite could be carved only by hand tools with generally poor results.


“Uses of Granite”.

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Other Rock Types

Granite ballast
Granite ballast
Rock Types

Decomposed Granite Ballast

Decomposed granite aggregate is often chosen as the decomposed granite ballast used to support the rails in railway construction. As with roadbuilding, granite aggregate is popular with track layers due to its strength, durability, and excellent drainage-promoting qualities.

Granite is the most common igneous rock (rocks formed through the cooling and solidification of magma or lava) on Earth. In the case of granite, it originally crystallizes below Earth’s surface, where its slow cooling allows large crystals to form. You may have seen granite take shape as some of America’s favorite sights like Yosemite Valley or a few guys on Mount Rushmore. Granite has also been mined and used for daily applications for thousands of years, from ancient hand tools to modern-day countertops.

Decomposed granite is the completely natural derivative of granite. When granite erodes and endures weathering over time, it easily starts flaking and crumbling away from its parent source. This decomposed granite crumbles into various sizes of particles and can be further crushed and screened to specific sizes for different project needs. Granite weathers into decomposed granite in part because one of its components, feldspar, chemically weathers into a clay mineral called kaolin, which, when exposed to more water, further deteriorates.


Although there are at least 30 colors and varying degrees of particle sizes, decomposed granite basically comes in three forms: natural, stabilized, and resin-coated.

  • Natural DG is used as a mulch material and can be spread around trees and garden beds much like wood mulch. It will continue to weather after it is put in place and provides nutrients to surrounding soil and plants. It lasts longer than most other mulch materials and will not attract pests.
  • For a path or patio, DG with stabilizers (which serve as a binder) is the best solution. Stabilized DG is often added on top of another gravel material, tamped down, then left with a thin loose layer on top.
  • DG with resin for driveways has a similar surface to asphalt, but has a more natural look and is permeable.


Decomposed granite as a crushed stone form is used as a pavement building material. It is used on driveways, garden walkways, bocce courts and petanque terrain and urban, regional, and national park walkways and heavy-use paths. DG can be installed and compacted to meet handicapped accessibility specifications and criteria. Different colors are available based on the various natural ranges available from different quarry sources, and polymeric stabilizers and other additives can be included to change the properties of the natural material. Decomposed granite is also sometimes used as a component of soil mixtures for cultivating bonsai.

While DG is most commonly used for paths, driveways, garden trails, and as a xeriscape ground cover, it can also be used to create smooth visual transitions between formal garden and wilderness. One of its advantages is that it breaks down, so any DG that migrates into a lawn or planting beds does not cause problems the way gravel does. Lining a path or patio with a black metal strip (which will disappear if buried low enough) will help keep it in place.



A Short Guide to What You Need to Know about Decomposed Granite. KAFKA GRANITE.
Hardscaping 101: Decomposed Granite. GARDENISTA

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Other Rock Types

Rock Types

Limestone Ballast

Limestone aggregate is often chosen as the limestone ballast used to support the rails in railway construction. As with roadbuilding, limestone aggregate is popular with track layers due to its strength, durability, and excellent drainage-promoting qualities.

Ballast is made of limerick from 1 inch to 2 1/2 inches in size. The product is commonly used as erosion control, for heavy drainage, as a stabilizer or for landscaping. It can be used for unique build driveways, for example, on muddy roads, and typical driveways.

The limestone Ballast supports the railroad ties. Because ballast is a large one-size, angular rock, it allows water to drain away from the track. The process of placing the ballast around and under the railroad ties and track is called tamping the track. The ballast supports and levels the track. The ballast also helps keep undesirable vegetation from growing in the tracks

Other Usage

Limestone blocks have been used in building since ancient times – perhaps most notably in the construction of the Great Sphinx and pyramids in Ancient Egypt over 4,000 years ago. And the Romans used local limestone aggregate to build solid foundations for nearly 2,000 miles of roads throughout Britain during their four centuries of occupation (43-410 AD).

Over the centuries, the flexibility of limestone aggregate has been gradually uncovered. The limestone is softer than granite or trap rock. It fractures and abrades more easily under load. It produces foul drainage fines to a greater extent than the harder rock product. Far from being just a humble by-product of quarrying, limestone aggregate is a remarkably versatile material. It’s also very much in demand for public, commercial, and residential uses. Railroad ballast is typically graded from 1 ¾” or 1 ¼” to ½.” The ballast is open graded and washed over a screen as part of the production process.



  • Concrete Production: Probably the most widely used worldwide construction material, concrete is made from a mixture of cement, sand, and water. Adding a coarse aggregate (often made from crushed limestone) builds in extra strength to the finished concrete.
  • Road building: Limestone aggregate is commonly used in roadbuilding, where a robust and robust base is needed to withstand the weight of traffic. Limestone aggregate creates a sturdy and durable foundation on which to lay the tarmac or asphalt. You’ll also often see limestone aggregates used in channels at the roadside (or on the central reservation) to help with run-off drainage.
  • Underground pipe bedding: With underground pipes, limestone aggregates are often used as a bedding layer for the pipes. Limestone doesn’t expand or contract. The limestone aggregate protects and insulates the pipe from any soil movement caused by temperature changes, moisture, or external factors such as traffic passing above.


Limestone aggregate – not just a chip off the old block!.

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Other Rock Types

Rock Types

Basalt Ballast

Basalt ballast are common aphanitic igneous extrusive rocks composed of minute grains of plagioclase feldspar (labradorite), pyroxene, olivine, biotite, hornblende, and less than 20% quartz. Basalt is dark grey rock which varies from almost featureless to spotted. Basalt is a herd black volcanic rock which is the most common type in the earth’s crust. Depending on how it is erupted, basalt can be hard and massive or crumbly and full of bubbles.

Beaches underlain by basalt usually include a variety, some with spots, and some that are uniformly gray. Basalt have bubbly flow tops, and these fill with a variety of colored minerals. Basalt ballast meets rail ballast specifications and provides effective stability. Basalt is a main line today as it can stand up to grinding action of passing trains without producing too many fine particles that could clog things up.


  • Ophitic basalt or Ophite is rare and comes from the flow interior and has uniform spots which are usually lighter and harder than the rest of the rock.
  • Pegmatoid pegmatitic basalt o dolerite is also very rare and is from the flow interior and has white crystals which are conspicuous.


  • Basalt rock is great for paths under bricks or paves also.
  • Basalt has superior thermal and acoustic properties in rock wool insulation
  • Higher than average strength in specialty applications
  • Use on railroad for ballast


  • Basalt is excellent for railroad track ballast because of its insensitivity to chemical influences, resistance to mechanical stress, high dry relative density, frost resistance, and sea water resistance
  • Basalt is among the hardest form of rock and according to the Moh’s scale in the US, basalt is ranked 8-9 and categorized as critically hard. In addition to its natural firmness, it also has a high modulus of elasticity, and is considered extremely durable and can withstand even the toughest weather conditions. Thanks to its hardness and durability, basalt has become a favorite for railroaders, landscapers and modelers.
  • Because of its high modulus of elasticity, basalt is ideal for high-strength applications. It is also naturally fire-resistant making it also ideal for high temperature applications.


Trap Rock Supplier. SUNROCK. 
PROFI Ballast “Basaltic Rock”. 

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Other Rocks

Basalt Ballast
Basalt Ballast
Rock Types

Cinder Ballast

Cinder, also known as “lava rock,” is used for railroad ballast. You can use it for running tracks, baseball infields, driveways, pathways, flower beds, hydroponic and aquaponics. Cinder is very porous and weighs less than half that of other landscape materials. It has excellent drainage properties and is erosion resistance. Cinder provides optimum drainage to a bed, making it suitable for low-lying areas that collect water or for plants that prefer drier growing conditions. It is ideal in areas where you want minimal maintenance and plans to grow native or low-maintenance perennial shrubs, trees, and plants.

Other Usage 

The rocks are best for areas where the ground is rarely disturbed, and the stones can remain a permanent part of the landscape. Cinder ballast is a crushed volcanic rock that gets its appearance from the simultaneous rapid cooling and depressurization process after being ejected out of a volcano. Cinder ballast has small cysts, which is what causes it to be so light in weight. These vesicles help to retain nutrients and moisture when used as a soil amendment and will also help with drainage as it creates excellent pore space in the soil. It also does not attract fungi, nematodes, or insects.

Additional usage

Cinder Sand used as an infield and warning track component for baseball fields. Cinder as decorative purposes in landscaping. Cinder rocks are lava cinders screened to two sizes: Large (3⁄4″ – 11⁄2″) and Small (1⁄4″ – 1⁄2″).  Cinder rock seems to be the hands-down favorite for replacing an old patch of grass with decorative ground cover.

  • Soil Amendment
  • Use as a mulch for shrub and plant beds to conserve water and limit weed growth.
  • Cinder makes exciting garden pathways and decorative borders around flower beds.
  • Infield & Warning Track Component
  • Decorative Purposes for Landscaping


  • Use approx. Three inches for an application to control weeds and retain moisture in the soil.
  • Pathways and decorative borders can use approx. 2″- 3″ depending upon the location.
  • Amending soil, mix 10% of Cinder Sand with dirt. Percentages vary depending on the type of gardening project. Plants, flowers, cactus, trees, etc.
  • For adding as an Infield or Warning Track component, try mixing with our A-1 Infield Soil as the colors nicely blend.


• “Red Cinder Rock”. LANEFOREST. Retrieved April 26, 2020 from
• “RED CINDER SAND”. LEHIGH HANSON. Retrieved April 26, 2020 from

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