gleis_neun
Point Cloud Simplification: The Discipline of Honest Deletion
How rational decimation keeps a laser scan light and geometrically honest for scan-to-BIM — from Song & Feng curvature to GP-PCS, with a one-line Open3D check.
Zürich–Winterthur: the three-minute tunnel that is really buying a spare path
SBB's MehrSpur Zürich–Winterthur isn't buying three minutes but redundancy — and why usable possession hours, not spans, set a build's programme.
Infrastructure Systems Design: why the honest engineer solves the whole web at once
A PAZ foundation essay on Infrastructure Systems Design: coupled constraints, NSGA-II Pareto fronts, and why the honest engineer optimises cost, carbon and resilience together.
Two Clocks: Why the Grid, Not Your Building, Decides When You Open
The IEA's Electricity 2026 shows a five-to-fifteen-year grid clock behind every one-to-three-year build. On any electrical load, own the connection date.
The half-built tunnel comes due: what the Lötschberg's empty bore says about deferring fit-out
Switzerland's half-built Lötschberg Base Tunnel goes to full expansion — CHF 1.7bn, objection window closes 15 Sep 2026. What deferred fit-out really costs.
Six centimetres over 29.1 km: the Brenner's real deliverable was the survey net
The Brenner's real deliverable was a traverse that closed 6 cm over 29.1 km — and why the as-built survey net belongs in your next BEP as a signed deliverable.
The World's Highest Bridge Is a 625-Metre Sensor: What Huajiang Teaches the Desk
The world's highest bridge embeds fibre load cells in 3 of 217 cable strands. Why the monitoring plan, not the record height, is the real engineering story.
The Gotthard kept two bores and still lost thirteen months to a shared door
Europe just cut the freight-wheel inspection interval after the 2023 Gotthard derailment. The deeper lesson: redundancy sharing a joint is one path there.
Watching thirteen kilometres of Betuwe freight rail settle, one millimetre at a time
University of Twente fused 170 Sentinel-1 radar scenes with national LiDAR to flag the soft-soil Betuwe freight segments subsiding 30 mm before any survey train.
The Control Layer Dies First: SBB's CHF 280m Bet on Keeping Iltis Alive
SBB pays Siemens up to CHF 280m to keep 30-year-old Iltis alive to 2045 — a lesson in single-vendor lock-in and the certification chain buildings ignore.
