Supply-chain lens — end-consumer attribution for rail freight

This page sets out the attribution rules and the analytical scope of the supply-chain lens, the fifth published view of the UK rail freight network alongside operators, ports, inland terminals, and corridors. The league-table methodology and the data-window methodology describe the underlying attribution machinery and observation boundary that this page builds on.

What the supply-chain lens measures

Every rail freight service in Great Britain originates or terminates at a physical site. The operator, port, inland-terminal, and corridor lenses describe the railway that conveys the freight; the supply-chain lens describes the industrial site that ordered it.

A supply-chain entity in the published archive is a single end-consumer operation whose rail-freight activity is large enough, stable enough, and attributable enough to publish as its own reference page. The eight pilots live at v1.0 launch — Drax, Margam, Scunthorpe, Westbury, the Mendip quarries, Boulby, Peak Forest, and Earles Sidings — are the largest single-site rail-served end consumers in the live TRUST data window. The selection is deliberately conservative; smaller sites and aggregate categories (nuclear logistics, defence logistics, infrastructure-project flows) are scoped on the supply-chain index page but report in aggregate or remain out of scope at v1.0.

Why the lens is necessary

The other four lenses report performance of the railway. A reader who wants to know how reliably the rail network delivered to a particular industrial site has to reconstruct that view by intersecting operator movements, corridor traversals, and terminal arrivals. The supply-chain lens does that reconstruction directly: the published figures for Drax describe the inbound and outbound rail flow at Drax, regardless of which operators carried the wagons or which corridors they traversed to get there.

This is the view a procurement director at British Steel, a logistics manager at Tarmac, or a fuel-supply planner at Drax cares about when they read a freight performance report. The four railway-side lenses are necessary inputs to that view but they do not assemble it. The supply-chain lens does.

Attribution rule

Every figure on a supply-chain page is computed by destination or origin TIPLOC, using the same TRUST data and the same on-time threshold described in the data-window methodology and the league-table methodology. A site is defined by its set of terminating TIPLOCs in the Network Rail reference data. The complete set of identifying codes is published on every supply-chain page under the TIPLOC footprint heading.

Inbound journeys are non-cancelled freight services whose schedule destination TIPLOC is in the site’s footprint set. Outbound journeys are the same with the schedule origin TIPLOC in the set. A2F (arrival within fifteen minutes) is computed on the inbound completed sample, matching the port and inland-terminal attribution rules.

Where a single physical site corresponds to multiple CORPUS records — for example Boulby, which appears as both BOULFHH (the rebranded Freightliner Heavy Haul reception) and BOULBYR (the legacy mine TIPLOC) — every record is included in the footprint set. The published total is the union, not a single record.

Carrier mix, not carrier ranking

Supply-chain pages publish carrier mix — what share of each site’s rail flow each operator carries — but they do not rank operators against each other on the site. Carrier mix is descriptive: the published archive reports which freight operating companies serve the site and in what approximate proportions, attributed by TRUST toc_id. It is not an attempt to grade them on their performance at the site.

The reason is that supply-chain rail flows are typically operated under multi-year freight contracts negotiated bilaterally between the end consumer and one or two operators. The mix observed in TRUST in any given 90-day window is the outcome of those commercial arrangements, not an open market. Ranking operators on a contracted flow would impose the operator-league-table interpretation on a population that does not share its statistical structure — the question “who arrived first” does not have a clean answer when only one carrier ever runs the service.

Operator-level reliability is reported on each operator’s own page and on the per-period operator reports.

Period reporting for supply-chain entities

Each supply-chain pilot will publish per-period reliability figures at /periods/<slug>/<period>/ as the data window accumulates closed periods of clean TRUST observation. The supply-chain period reports follow the same structure as the port and inland-terminal reports: services monitored, A2F headline, trailing baseline once available, carrier mix for the period, and the four statistical artefacts (partial pool, median polish, SPC, CLR) that all archive period reports carry.

Trailing baselines on supply-chain pages are reported as — until the data window covers at least twelve closed periods, on the same rule as the operator, port, and inland-terminal lenses. The data-window methodology gives the full boundary for what is observed and what is inferred.

What the lens does not cover at v1.0

The supply-chain index page sets out three categories that are scoped but not published per-entity at v1.0: nuclear logistics, defence logistics, and major infrastructure-project flows. The reasons are operational sensitivity (nuclear, defence), commercial sensitivity pending operator and licensee review (nuclear), and attribution model mismatch (infrastructure projects move through pass-through yards without project-specific TIPLOCs and would require a train-UID or operator attribution rather than the TIPLOC-set rule above).

These categories will move into per-entity coverage as the underlying data model and the disclosure framework allow. The release-cadence methodology sets out how new entities and new lenses enter the published archive.

How to read a supply-chain page

The page identifies the site, lists its TIPLOC footprint, reports the carrier mix observed in the live TRUST window, and links to the per-period reports as they publish. The carrier-mix percentages on each page carry the date the figures were queried in the prose, so a reader who returns to the page months later can see when the snapshot was taken. Per-quote re-dating, on the release-cadence schedule, replaces the snapshot with the next data-window close.