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 2 adds the Freight sheet and corrects the author's affiliation. Version 3 corrects two coordinate errors in the length derivation, adds the settlement coordinates to the Geometry sheet so that every derived length can be recomputed by the reader, and adds the article's two figures with the scripts that generate them. Corrections in version 3:- The northern section is now derived from Meydanekbez, the border station of the proposed alignment, instead of Cobanbey. Deriving from Cobanbey compared a different route to the engineering alignment and produced a 52 per cent section error; from Meydanekbez the same section differs by 10 per cent.- Nasib and Jordan's Jaber are the two names of one border crossing and are now treated as a single point at 32.5286 N, 36.2008 E. They were previously two points 37 km apart, and the distance between them was counted in no section. Effect on the results: the derived length of the missing link moves from 771 to 802 km against an engineering alignment of 800 km, the largest section-level error falls from 52 to 17 per cent, and the two independent estimates of new construction now differ by 2.4 per cent instead of 5 per cent.