Mendip Quarries — Period 13 2025-26 (1–28 March) report
Mendip Quarries handled 701 monitored inbound services and 683 monitored outbound services in Period 13 2025-26, the highest monitored endpoint count of any supply-chain site in the published archive. Inbound arrivals read 80% within 15 minutes of schedule against a national freight benchmark of 90%; outbound services read 88% within 15 minutes. Inaugural per-site supply-chain period report; the Period 12 2025-26 trailing baseline is below the publishable threshold, so no comparison against the prior period is published.
- Edition
- v1.0 (industry review edition)
- Last updated
- 28 March 2026
- Next update
- Period 1 2026-27 — 21 May 2026
Headline facts and figures
Services monitored (inbound)
701
queried gauge_intelligence_v2 at 2026-05-25; 25 a day across the six Mendip tiplocs (WHATFHH, WHATGBF, WHATLYQ, MERHFHH, MERHGB, MERHDQ); Period 13 2025-26 (1–28 Mar 2026); NROD-derived arrivals data; the Period 12 2025-26 trailing baseline is below the publishable threshold for a defensible comparator
Within 15 minutes (inbound)
80%
queried gauge_intelligence_v2 at 2026-05-25; 561 of 701 completed inbound services arriving within 15 minutes of schedule (range 77–83% given the sample size); national freight benchmark 90% over 16,826 services in Period 13 2025-26
Services monitored (outbound)
683
queried gauge_intelligence_v2 at 2026-05-25; 24 a day across the six Mendip tiplocs (WHATFHH, WHATGBF, WHATLYQ, MERHFHH, MERHGB, MERHDQ); Period 13 2025-26 (1–28 Mar 2026); NROD-derived departures data; the Period 12 2025-26 trailing baseline is below the publishable threshold for a defensible comparator
Within 15 minutes (outbound)
88%
queried gauge_intelligence_v2 at 2026-05-25; 601 of 683 completed outbound services departing within 15 minutes of schedule (range 85–90% given the sample size); national freight benchmark 90% over 16,826 services in Period 13 2025-26
Context
ORR publishes aggregates only; this page publishes site-attributed supply-chain data with inbound and outbound directions reported separately. Material to bulk-flow planning, quarry siding allocation, and corridor performance reviews.
What you can do with it
- Track inbound arrivals and outbound departure reliability at a single supply-chain site.
- Compare operator-by-operator reliability on services to and from a quarry cluster.
- Cite the methodology in aggregates planning and corridor reviews.
Who can use it
Quarry operators · Aggregates planners · Rail journalists
Across Period 13 2025-26, roughly inbound trains a day arrived at Mendip Quarries more than 15 minutes late and roughly outbound trains a day departed more than 15 minutes late, across 689 completed inbound arrivals and 671 completed outbound departures over the 28-day period. Mendip is the largest supply-chain endpoint by monitored journey volume published in this archive — the four quarries collectively produce around half of the rail-served aggregates moved in England. This report carries inbound and outbound figures as twin panels: inbound services bring empty wagons into Whatley and Merehead; outbound services depart loaded for the south-east and London markets. Figures aggregate every monitored journey at the six Mendip tiplocs in Network Rail's NROD/TRUST feed. The Period 12 2025-26 trailing window is below the threshold for a stable comparator; subsequent periods will carry the comparison against the prior period. Cancellations are reported separately below.
Inbound — services arriving at Mendip Quarries
Operators at Mendip inbound
Freightliner Intermodal ran the most mendip inbound services in Period 13 2025-26 (432 of 689 completed arrivals). The full per-operator reliability comparison is deferred while the v1.0 industry review edition corrections inbox remains open.
Publishing a per-operator on-time comparison for the busiest freight operators at a single destination before the launch-cohort corrections cycle closes would treat provisional attribution as settled. The table returns at v2.0 general availability. The league-table methodology documents the comparison framework; the release cadence page sets out the four exit criteria for v2.0.
Source: Gauge Intelligence NROD-derived journey data, Period 13 2025-26. Single-destination headline figures (completed arrivals, aggregate within-15-minute rate, cancellations) continue to appear in the panels above; the per-operator breakdown is the panel deferred here.
What the 15-minute threshold hides
Half of Period 13 2025-26 services arrived early — the median was 3 min ahead of timetable. The long tail the A2F binary misses: 5% of services ran +58 min or more late, and 1% arrived over +152 min late. The 15-minute A2F threshold sits at the 81th percentile — 19% of services exceeded it.
| Percentile | Arrival delay |
|---|---|
| 50th percentile (median) — A2F threshold sits at the 81th percentile | -3 min |
| 75th percentile — A2F threshold sits at the 81th percentile | +8 min |
| 85th percentile | +20 min |
| 90th percentile | +36 min |
| 95th percentile | +58 min |
| 99th percentile | +152 min |
689 services with confirmed terminal arrival in Period 13 2025-26. A2F is binary at 15 minutes — this distribution surfaces what the headline figure does not show. National 99th percentile across all freight operators: 98 min.
ORR's Freight rail usage and performance release publishes by Network Rail region and route, not by operator. This page publishes by operator and corridor.
Cancellation rate
No scheduled paths or activated journeys recorded for Period 13 2025-26.
Outbound — services departing from Mendip Quarries
Operators at Mendip outbound
Freightliner Intermodal ran the most mendip outbound services in Period 13 2025-26 (419 of 671 completed arrivals). The full per-operator reliability comparison is deferred while the v1.0 industry review edition corrections inbox remains open.
Publishing a per-operator on-time comparison for the busiest freight operators at a single destination before the launch-cohort corrections cycle closes would treat provisional attribution as settled. The table returns at v2.0 general availability. The league-table methodology documents the comparison framework; the release cadence page sets out the four exit criteria for v2.0.
Source: Gauge Intelligence NROD-derived journey data, Period 13 2025-26. Single-destination headline figures (completed arrivals, aggregate within-15-minute rate, cancellations) continue to appear in the panels above; the per-operator breakdown is the panel deferred here.
What the 15-minute threshold hides
Half of Period 13 2025-26 services arrived early — the median was 1 min ahead of timetable. The long tail the A2F binary misses: 5% of services ran +33 min or more late, and 1% arrived over +86 min late. The 15-minute A2F threshold sits at the 89th percentile — 11% of services exceeded it.
| Percentile | Arrival delay |
|---|---|
| 50th percentile (median) — A2F threshold sits at the 89th percentile | -1 min |
| 75th percentile — A2F threshold sits at the 89th percentile | +3 min |
| 85th percentile — A2F threshold sits at the 89th percentile | +9 min |
| 90th percentile | +17 min |
| 95th percentile | +33 min |
| 99th percentile | +86 min |
671 services with confirmed terminal arrival in Period 13 2025-26. A2F is binary at 15 minutes — this distribution surfaces what the headline figure does not show. National 99th percentile across all freight operators: 98 min.
ORR's Freight rail usage and performance release publishes by Network Rail region and route, not by operator. This page publishes by operator and corridor.
Cancellation rate
No scheduled paths or activated journeys recorded for Period 13 2025-26.
What this report doesn't yet carry
Four blocks routinely carried on more mature period reports are absent here, and the gap is disclosed rather than papered over:
- Partial-pool operator league table. The supply-chain artefact track is not yet wired into the archive renderer — the partial-pool, median-polish, statistical process control (SPC), and compositional log-ratio panels do not yet emit for supply-chain sites. Inbound and outbound flows at a quarry cluster behave as two distinct populations (different operator mixes, different timetabling pressure), and the partial-pool shrinkage assumption needs separate calibration for each direction. The block is suppressed pending that calibration.
- SPC process-behaviour chart. Mendip has four weekly A2F (arrivals-to-fifteen-minutes) points per direction in Period 13 2025-26; the signal rules require eight weekly observations before a stability or anomaly claim can be made. The block is suppressed.
- Median-polish operator-by-week matrix. The row-by-column operator-by-week decomposition requires a minimum number of journeys per weekly cell for each operator present. At this inaugural baseline depth the matrix is not yet sufficiently populated to publish without degeneracy. The block is suppressed.
- Compositional delay-reason breakdown. Network Rail's Historic Delay Attribution (HDA) feed for Period 13 2025-26 has not been imported at the as-of date of this report. Raw percentage-share comparison is misleading when shares are constrained to sum to 100% — an increase in any one cause forces a decrease in another — so the block is suppressed rather than substituted with a naked share. See the delay-attribution methodology.
The 12-week trailing baseline window (7 December 2025 to 28 February 2026) carries fewer than ten monitored journeys per direction — its 90% range spans a band too wide to anchor a defensible change against the prior period, so this report does not quote one. Baseline depth becomes informative once a full quarter of monitoring has cleared, expected from Period 2 2026-27 onward.
Each of the suppressed blocks above unlocks as baseline depth grows. The first follow-up period (Period 1 2026-27, closing 25 April 2026) adds four more weeks of monitored journeys, after which the weekly SPC threshold per direction and the operator-by-week matrix become candidates for inclusion.
Methodology & sources
All figures derive from Network Rail's NROD TRUST feed, processed via the Gauge Intelligence ingest pipeline. Period definitions, A2F (Arrival to Fifteen), the Wilson 90% interval, daily anomaly rules, cross-view reconciliation, and delay attribution are documented at:
Data window — period boundaries and the data-as-of cutoff
League tables — cross-view reconciliation across the four analytical views
Anomaly detection — daily A2F SPC rules
Delay attribution — DAPR cause-code breakdown
Forecasting — prediction intervals and possession-exposure estimates
Three further reads sit behind the commercial licence: a Schedule 8 net-position figure netting the FOC-to-Network-Rail differential against payments the other way; a full Delay Attribution Performance Report breakdown attributing each cause-code's contribution by sample weight; and a Schedule 4 possession-exposure read tracing how planned blockades intersect quarry-bound path allocation. None is yet substantively informative at Mendip's current baseline depth — the period count that suppresses the SPC chart above leaves each licensed read with too few points to anchor. The licensed access page sets out the methodology behind each.
Revisions
No revisions to date.
A revision restates a published figure because the upstream data changed, typically a Network Rail delay-attribution refresh. The minor tier is corrected in the next release; cells affected carry an (r) flag. The intermediate tier triggers immediate amendment with an (r) flag. The wholesale tier is flagged at the top of the page and notified directly to operators and rail journalists subscribed to revision alerts.
Corrections
No corrections to date.
A correction fixes an error in the published output: an arithmetic slip, a typo, a mis-rendered chart. Revisions are different; they restate a figure because the upstream data changed. The distinction matters because corrections never silently rewrite a published number.