Slab track construction

Stabirail’s innovative bottom-up slab track construction method revolutionizes railway infrastructure by combining efficiency, precision, and sustainability. Designed to address the challenges of traditional rail systems, this groundbreaking approach ensures durability, reduced maintenance, and unparalleled adaptability for various environments, including tunnels and bridges.

The construction process: step-by-step

Stabirail’s bottom-up slab track method employs a meticulously engineered sequence using advanced machinery and techniques to achieve unmatched precision and efficiency.

Step 1: Constructing the concrete beam

The foundation of the slab track is the concrete beam, which is constructed as follows:

• Earthworks: if needed, prepare the site by leveling and compacting the ground.
• Concrete foundation: if needed, lay a base layer of lean concrete to stabilize the foundation.
• Rebar placement: install reinforcement bars for structural strength, taking in account future rail anchor position.
• Formwork installation: set up formwork to shape the concrete beam.
• Concrete pouring: pour and cure the concrete to ensure a strong and durable base.
• Formwork removal: once the concrete has cured, remove the formwork.

Steps 3-6 can be replaced with a 3D slip-form paver and fiber-reinforced concrete. In case rebar installation is needed, the slip-form paver can still mold the concrete without formwork.

This creates a stable and precise base that is ready for the rail system installation.

Step 3: Diamond-core drilling

After milling, the next step involves drilling precise holes into the concrete slab for anchoring the rails. First, we position the fully assembled track onto the concrete slab in its exact alignment. The rails are securely attached to the soleplates and temporary fastening rods are used to hold the track in place during the process.
A specialized drilling machine runs along the track to bore precise holes through the soleplates into the concrete base. The use of diamond-core drills or percussion drilling ensures:

• Minimal vibration: reducing impact on surrounding structures, crucial for urban and tunnel environments.
• Dust-free operation: equipped with advanced filters to reduce emissions during tunnel work.
• Efficient execution: automated processes ensure consistent and accurate drilling.
• Anchoring precision: ensures secure fixing points for the rails.

These anchor points are vital for securing the rails and maintaining track stability over decades of use.

Step 4: Rail anchoring

Once the anchor points are drilled, the rails are secured to the concrete bed using specialized anchoring systems. This step ensures:

• Track stability: no longitudinal or lateral movement under high-speed and heavy-load conditions.
• Load distribution: the rigid slab evenly disperses the dynamic forces from trains, reducing wear and tear on the superstructure like tunnels or bridges.

Stabirail’s method avoids the challenges of traditional rail alignment processes, such as shifting due to temperature changes, concreting or due to unwanted movements of personnel or equipment during installation.

Installation process:

• Cleaning: the drilled holes are thoroughly cleaned using a water vacuum to remove debris and ensure proper adhesion. If drilled by a diamond core drill, removal of the drilled core.
• Control: checking the required installation depth and adjustment if needed
• Adhesive injection: a two-component adhesive is injected into each hole to provide maximum strength and stability.
• Anchor installation: rail anchors are inserted into the adhesive-filled holes with precision.
• Tightening: each anchor is tightened to the exact torque specification required for optimal performance.

This anchoring process guarantees accurate and robust support for high-speed and heavy-load rail traffic.

Step 5: Quality assurance and alignment checks

Stabirail employs advanced 3D measurement systems to verify the alignment and positioning of the installed rails. These checks ensure:

• Accurate geometry: guaranteeing smooth operations and minimal wear on rolling stock.
• Long-term reliability: preventing deviations that could lead to costly maintenance.

This rigorous quality control is a significant upgrade over conventional methods, where alignment issues are often corrected post-installation.
Stabirail is fully compliant with regulatory standards. We’re VCA, ISO9001 en ISO45001 certified. Read more about us here.

Advantages over traditional methods

Stabirail’s bottom-up slab track offers significant advantages compared to traditional methods like sleepers embedded in concrete and prefabricated ballastless tracks:

Traditional methods

1. Sleepers embedded in concrete:

• Complicated and time-consuming installation with the use of very heavy and special equipment and a big workforce.
• Difficult and slow to repair, requiring complete removal.
• Susceptible to cracking due to material layers with different expansion coefficients and aging of the elastic materials.

2. Prefabricated ballastless tracks:

• Convenient pre-assembly but high transport requirements.
• Complicated to install in tunnels due to lifting height limits
• Requires extensive alignment work.
• Multiple design variations needed for curves and gradients, complicating design and increasing costs.

3. Other disadvantages:

• Difficulties in adjusting or correcting track geometry once concrete has been set
• Specific rail systems are needed leaving no options for the client
• Use of grout or other mix of materials complicate installation processes and limit recycling and circularity at end of lifetime or during maintenance.

Bottom-Up slab track

• One unified structure: eliminates the need for multiple material layers, reducing risks of deformation and cracking.
• Design flexibility: supports complex track geometries, including sharp curves and steep gradients, using slipform paving technology.
• Weather independence: ensures uninterrupted progress regardless of rain or freezing conditions.
• Repairability: easy and straightforward repair methods, enable targeted interventions in case of damage without major disruption.
• Compatibility: independent of fastening systems, offering flexibility in choosing rail system suppliers based on project requirements.

The benefits of Stabirail’s bottom-up slab track construction are numerous, for a detailed breakdown of these advantages, read our Advantages page.

Why choose Stabirail?

Stabirail’s method is more than just a construction process—it’s a paradigm shift in railway infrastructure:

• Efficiency: faster construction with reduced project timelines.
• Safety: the bottom-up construction sequence avoids coordination conflicts during the different steps and parties involved
• Durability: systems designed to last over 60 years with minimal maintenance.
• Sustainability: lower material usage and reduced environmental footprint.
• Precision: industry-leading accuracy of up to 2mm.

Whether built through tunnels, over bridges, or on open terrain, Stabirail’s bottom-up slab track is the superior choice for future-proof railway infrastructure.