Supplementary Material S1: Reproducible cost and market model for the Hejaz rail corridor's missing link

Reproducible cost and market model supporting the article "Alternative Financing Models for Reviving the Hejaz Railway: A Reproducible Cost and Market Estimate for the Missing Link". The workbook contains the inputs and calculations behind the article as live formulas. Any assumption can be changed and the model recomputed. Contents:- Assumptions: unit costs, scenario levers and the exchange rate, each with its source and the caveat attaching to it.- Geometry: section lengths for the corridor, derived from published settlement coordinates by great-circle distance and a circuity factor calibrated on two existing railways.- Cost: capital cost of the missing link and the proposed Ha'il-Madinah extension, with AACE estimate class and reference-class uplift.- Demand: overland pilgrim arrivals from the Saudi General Authority for Statistics Hajj and Umrah bulletins, converted to rail journeys.- Presale: the advance-purchase instrument sized against the published external Umrah population.- Engineering: the author's own engineering estimate for the proposed alignment, and its comparison with the published-source estimate on a common scope.- Freight: the author's own corridor freight estimate, with published regional comparators and the evidence that works against it.- Sources: every source used, with URL. The cost and market work is built entirely from published sources. Two quantities are not: the author's engineering cost estimate and the corridor freight estimate. Both are the author's own, both are labelled as such where they appear, and neither is relied on for a result the published-source work does not reach independently. Scope note: the workbook contains no operating cost, tariff, revenue, subsidy requirement or benefit-cost analysis. It is a capital cost and market estimate, not an economic appraisal. Known weaknesses are listed on the README sheet and in Section 8.3 of the article. Version 4 adds the Freight sheet and corrects the author's affiliation.