The same Willington excavation report describes the main line's gauge as 'four foot eight inch,' with no half-inch — an internal inconsistency in the primary source itself

history-of-technologystandardizationrailroad-gaugewagonwaysgeorge-stephensoncontested

Summarising the same excavation whose siding measurement gives the full 4 ft 8½ in figure (see claim-willington-1785-siding-measured-4ft8-5in-same-gauge-as-main-line), Carlton and Williams's report states in its Conclusions: "The line comprised a main line of 'standard', four foot eight inch gauge, with single and double-rails laid on various kinds of wooden sleepers." This is the base 4 ft 8 in figure elsewhere associated with George Stephenson's pre-1829 practice at Killingworth, Hetton, and the Stockton & Darlington Railway (see claim-stephensons-4ft8in-gauge-predates-1829-only-final-halfinch-dated-there) — applied here to the main line rather than the siding, and never reconciled against the report's own siding measurement or its own "4' 8½" or 1.435 m" definition of "standard" gauge, which appears a few paragraphs later in the same Conclusions (in the passage on the site's international significance). Both formulations sit unreconciled in the same short Conclusions section.

This loose "four foot eight inch" framing is not a one-off slip in the source material: Newcastle City Council's Historic Environment Record, drawing on the same excavation report and the same Setting the Standard volume, independently records "The Willington Waggonway has a main line of 4ft 8" gauge" — the half-inch absent there too.