Product Title: Ultra-Realistic Historic Weathered Ashlar Tunnel Portal System

Short Description: A meticulously restored, photogrammetry-based ashlar stone tunnel portal, featuring realistic soot weathering, interior brickwork, and standard/double-stack train clearances.

The Details: This ultra-realistic tunnel portal system captures the heavy, structural reality of late 19th-century railroad infrastructure. The front features massive ashlar stonework that seamlessly transitions into a smaller brick liner inside the archway, utilizing a specialized micro-texture to represent rough-poured concrete without causing print stringing. It is specifically engineered with files that clear massive modern double-stack well cars alongside standard vintage equipment without clipping. To perfectly preserve the historic roof lip and inner arch details, this model is designed to be printed with standard tree supports.

Technical Specifications:

Native Scale: Designed for HO (1:87) - Scales up perfectly for O scale

Geometry: 100% Manifold, Watertight

Print Difficulty: Moderate FDM - Requires tree supports

/// FILES INCLUDED ///

• Modern_Double_Stack_Clearance_Thin_Facade.stl: A streamlined facade engineered with extended vertical clearance to accommodate modern intermodal well cars.
• Standard_Era_Clearance_Thin_Facade.stl: A historically proportioned facade perfect for steam and early transition-era rolling stock.
• Standard_Era_Full_Depth_Source_Wedge.stl: The massive, full-depth structural wedge for building complete, heavy-duty tunnel interiors.

Recommended Print Settings:

FDM: Print standing upright in their native orientation. To ensure the sharpest details on the heavy roof lip and a clean, sag-free inner arch ceiling, you must enable Tree Supports set to "Touching Buildplate" only.

Resin: Tilt the model 45 degrees backward to place all supports on the hidden rear surface to preserve the ultra-realistic front stone textures.