Choosing Ballast for Your Model Railroad
Ballast is one of the most noticeable features of any model railroad. It not only affects the appearance of the track but also contributes greatly to the overall impression of the entire landscape. The right ballast can make even a simple section of track look realistic, while the wrong ballast immediately reveals that it is a model.
Ballasted European prototype-style track with wooden sleepers.
Today there is a wide selection of commercial model railroad ballast available, and there are also countless articles on the Internet explaining how to make your own ballast from sand or other materials. Before deciding which method to use, it is worth understanding what railway ballast actually is and which properties are important for achieving a realistic and durable result.
From Gravel to Crushed Stone
The earliest railways were actually built without the type of ballast we know today. During the 19th century, sleepers were often laid directly in gravel or natural soil. Engineers soon discovered that the track quickly lost its alignment whenever the ground became wet or was subjected to repeated loads from passing trains.
By the beginning of the 20th century, crushed stone had largely replaced gravel as the preferred ballast material. The angular stones interlock with one another, firmly holding both the sleepers and the track in position far better than rounded gravel or sand.
Besides stabilizing the track, ballast performs several important functions:
- Distributes the weight of passing trains into the foundation.
- Provides efficient drainage of rainwater.
- Prevents vegetation from growing between the sleepers.
- Allows the track to be adjusted during maintenance.
For these reasons, the angular shape of the stones is just as important as their size.
What Makes Good Model Ballast?
Model ballast should not only look realistic—it must also behave properly when it is applied and glued in place. A good ballast material therefore has several important characteristics.
The Dellen Railway, inaugurated in 1888, originally used a sand trackbed.
The Particles Should Sink into the Glue
Ballast is normally fixed using a mixture of water, white glue (PVA) and either dishwashing detergent or isopropyl alcohol. If the ballast floats on the liquid, the particles will move during gluing and create an uneven appearance. A good model ballast sinks immediately and stays exactly where it is placed.
The Material Must Not Expand
Some organic materials absorb water and swell. This creates small ridges and bumps between the sleepers, ruining the appearance of the track. As the glue dries, the material often shrinks again, leaving cracks or causing the ballast to separate from the surface.
The Particles Should Not Separate
Some ballast products contain both light and heavy particles. When glue is applied, surface tension may cause the different particles to move by different amounts. Instead of remaining evenly mixed, fine and coarse particles collect in different areas. This effect can also be noticed using sand, like Chincilla sand
Size and Shape
The particle size should be appropriate for the scale being modeled. For H0 scale, ballast is typically between 0.5 and 1.0 mm in size. The shape of the particles is equally important. Real railway ballast consists of crushed stone with sharp, angular edges. Rounded sand grains rarely produce a convincing appearance.
Colour
Ballast colour varies considerably around the world. In Sweden, grey granite is common, while other countries may use brown, black, red or almost white ballast depending on the local rock types.
Mineralbaserad ballast med allt för mycket glas ger transparent utseende
och allt för runda korn ger blänka. Tillverkare: Noch "Balasltic dark gray".
Mineral-based ballast containing too much glass appears transparent, while excessively rounded grains create unwanted reflections. Manufacturer: Noch "Ballastic Dark Gray".* Before choosing ballast, study photographs of the railway you intend to model. Natural colour variation between individual stones is equally important. Completely uniform ballast rarely looks realistic.
Adjusting the ballast profile before gluing.
Manufacturer: Minitec "Rust Brown".
Today there are primarily two types of commercially available model ballast.
Mineral-Based Ballast
The most common type consists of crushed stone or coloured mineral sand. Its advantages include:
- Sinks easily into the glue.
- Retains its shape.
- Does not expand.
- Provides good weight and stability.
- Excellent long-term durability.
Quality does vary between manufacturers. The best products consist of genuine crushed stone with naturally angular particles.
Organic Ballast
Some manufacturers produce ballast from organic materials such as:
- Ground cork
- Crushed walnut shells
- Wood fibre
These materials are lightweight and often have an attractive colour and texture, but they frequently develop problems when exposed to water-based adhesives.
Homemade Ballast from Sand
Many articles on the Internet recommend using ordinary sand as ballast. Unfortunately, my own experience has been that the results are almost always noticeably inferior to commercial model railroad ballast.
Crushed walnut shells coloured in three different shades of brown.
I have experimented with several types of screened sand. The problems were almost always the same. First, the colour variation between individual grains was far too great. Some grains appeared almost white while others were dark grey or brown, producing an unnatural and distracting appearance. Secondly, sand grains are much smoother than crushed stone. Light therefore reflects differently, giving the finished track a "sandy" appearance rather than the look of a real railway. I also experimented with colouring the sand using powdered pigments. Unfortunately, much of the pigment washed away during the gluing process, resulting in an uneven finish. For these reasons, I cannot recommend ordinary sand as ballast for model railroads.
Homemade Ballast from Crushed Walnut Shells
For several years I also experimented with ballast made from crushed walnut shells. Walnut shell media is sold in large, inexpensive bags for cleaning cartridge cases before reloading ammunition. The particle size is often suitable for H0 scale, making it an attractive low-cost alternative. The shells were coloured using dry powdered pigments before being spread between the sleepers. Unfortunately, several problems appeared. As with the sand, much of the pigment washed away when glue was applied. Even more importantly, the walnut shells absorbed water from the glue mixture and began to expand. This produced small ridges of ballast between the sleepers, giving the track an unrealistic appearance and creating an uneven ballast profile. For Märklin users this creates an even bigger problem. As the walnut shells swell, they can lift the pickup shoe, preventing proper contact with the centre studs. The result is unreliable electrical pickup and poor running performance. After these experiments I returned to commercial mineral-based ballast.
Finished main line with mineral-based ballast.
My Recommendation
After experimenting with both homemade materials and many different commercial products, I have concluded that a high-quality mineral-based ballast is well worth the investment. It provides:
- Better appearance.
- Easier application.
- More reliable bonding.
- No expansion problems.
- Improved operating reliability.
Ballast represents only a small percentage of the total cost of a model railroad, yet it has a greater impact on the finished appearance than many details costing considerably more.
Comparison of Common Ballast Materials
| Material | Appearance | Expands in Glue | Particles Stay in Place | Behaviour During Gluing | Recommendation |
|---|---|---|---|---|---|
| Crushed Stone (Mineral-Based) | ★★★★★ | No | Excellent | ★★★★★ | Highly Recommended |
| Colored Sand | ★★★☆☆ | No | Fair | ★★★☆☆ | Acceptable |
| Natural Sand | ★★☆☆☆ | No | Poor | ★★☆☆☆ | Not Recommended |
| Crushed Walnut Shells | ★★☆☆☆ | Yes | Poor | ★☆☆☆☆ | Not Recommended |
Conclusion
Ballast is literally the foundation of realistic-looking track. Just as on the prototype, realism depends not only on colour and particle size but also on the technical properties of the material itself. Good model ballast should sink into the glue, retain its shape and create a natural texture between the sleepers. Although making your own ballast from sand or walnut shells may seem attractive, my experience has shown that commercially available mineral-based ballast almost always produces a significantly better and more durable result. Once the ballast has been glued, weathered and blended into the surrounding scenery, it will remain part of your layout for its entire lifetime. For that reason, this is one area where choosing quality from the very beginning is almost always worthwhile.
/ Martin T