Mainline Railworks HOn3 Sectional Tunnel Track System

🌄 Mainline Railworks HOn3 Tunnel Track System

Mainline Railworks HOn3 Tunnel Track Sections allow modelers to bring realistic elevation, scenery depth, and hidden track routing into their narrow gauge layouts using precision sectional tunnel track in both straight and curved configurations.

All tunnel sections are sold individually, giving you full flexibility to build exactly the tunnel length and geometry your layout requires.

Each piece is engineered to match Mainline Railworks HOn3 geometry standards, ensuring smooth transitions between visible and hidden track runs.

🚂 Why This Matters

Tunnels are not just scenic elements—they define how a layout feels and operates. They allow trains to transition between visible and hidden sections, simulate real mountain railroading, and add vertical storytelling to otherwise flat layouts.

📐 Tunnel Geometry Options

Mainline Railworks tunnel track is designed to integrate seamlessly with the same geometry system used throughout all HOn3 sectional track components.

🟡 Straight Tunnel Sections

• Sold per section

• Used for direct entry/exit routing through terrain

• Ideal for staging transitions and hidden return loops

• Provides clean alignment through scenic terrain

🔵 Curved Tunnel Sections

Curved tunnel track is available in multiple radius and angle configurations to match layout geometry and ensure smooth transitions through mountainous terrain.

• Sold per section

• Mix and match to create custom curves and tunnel lengths

📏 Radius Options

Curved tunnel sections are available in multiple radii to support:

• Compact tabletop layouts

• Shelf railroads

• Mining and logging branch lines

• Large scenic mountain mainlines

Smaller radii are ideal for tight terrain routing, while larger radii provide smoother, more prototypical mountain rail appearance.

📐 Angle Options

Curved tunnel sections are offered in the following configurations:

A — 22.5° sections (16 per full circle)
Balanced geometry for most layouts and smooth directional changes.

B — 11.25° sections (32 per full circle)
Fine adjustment geometry for precise layout design and smooth transitions.

C — 45° sections (8 per full circle)
Ideal for compact layouts and rapid directional changes in tight terrain.

🏔 Perfect For

• Mountain narrow gauge railroads

• Logging and mining operations

• Scenic shelf layouts with elevation changes

• Hidden staging loops and return tracks

• Compact tabletop and floor layouts

• Expanding starter loops into scenic railroads

🔧 Key Features

• Straight and curved tunnel track sections available

• Sold individually for maximum layout flexibility

• Precision-matched HOn3 sectional geometry

• Seamless integration with visible track systems

• Designed for both hidden and scenic routing

• Supports modular layout expansion and terrain modeling

🛠 Custom Tunnel Options

Custom tunnel radius and geometry configurations may be available upon request for specialized layout designs, prototype modeling, or unique scenic applications.

⚙️ Compatibility

• Compatible with Mainline Railworks HOn3 sectional track (Code 80 rail)

• Works with HO/HOn3 dual gauge systems

• Compatible with legacy Blackstone ProTraxx HOn3 geometry

• Integrates with straight, curved, feeder, and bumper track systems

• Suitable for temporary, modular, and permanent layouts

🚇 Portal Clearance Standard

Tunnel portals are designed in accordance with NMRA clearance standards for HO/HOn3 narrow gauge and old-time equipment, ensuring reliable passage for a wide range of locomotives, rolling stock, and scenic configurations.

➕ Pairs Well With

• Curved track sections (mountain routing)

• Straight track sections (approach alignment)

• Feeder track sections (hidden power routing)

• Starter Loop Sets (scenic expansion upgrade path)

• Bumper track sections (terminal scenic endpoints)

⚠️ Builder Tip

For the most realistic effect, curved tunnel sections should be paired with visible approach curves and elevation changes rather than placed immediately between two straight visible sections.