Ring by ring, the bore matches the alignment before the next push. The scan comes off the gantry between shoves, the drift is read against design in minutes, and the ground above is watched while the machine is still under it.
Capture · Mission 02
The sheet above is a drawing of this. 10 capture waypoints, and every finding called as the aircraft reaches it — scroll sets the target, the mission keeps its own pace, and the page waits for it.
Sector · Tunnels
Two hundred metres of lining, ring by numbered ring, with the drift read against the design alignment and the ground above watched while the machine is still under it.
As-built ring positions arrive as a spreadsheet a week after the shove. By the time a drift trend is visible on it, the machine has built forty more rings on the same tendency.
Each ring is scanned from the gantry and compared to the design alignment before the next push. Build tolerance, ovality and step read as numbers on the shift they happened, not as a memory of how the shove felt.
Settlement over the drive is somebody's monthly level run across a road that carries buses. A few millimetres under a listed façade matters, and monthly is not a schedule.
Surface markers along the alignment are captured on the same fix as everything else — ±1.2 cm on any point, repeatable flight to flight — and the movement is plotted against the ring the machine was on when it moved.
A segment chipped on the shove is argued about six months later, when the only evidence is a photo on somebody's phone and nobody can say which ring it was taken at.
A 360 walk of the completed rings pins every frame to its ring number. Damage, grout ports and cross-passage breakouts are found by scrolling the drive instead of booking a possession to walk it.
2,140
Rings built and measured on drive 2
±8 mm
Drift from the design alignment
22 m/day
Advance held with the record current
The program runs on the shove cycle. The bore is never flown — the record comes off the gantry and the trolley — and the only flight is the corridor overhead, watching the ground while the machine is still under it.
Every shove, from the gantry
Ring 2140 was built at 02:44 and scanned at 03:18 — 34 minutes from shove to surface. Build tolerance, ovality and step read against the design alignment before the machine pushes again.
SPACING 4MM · REG 3MM RMS · ØI 8.80MEvery 10 rings, behind the backup train
A mobile scanner runs the completed drive at walking pace and refreshes the as-built without stopping the belt. At twelve rings a day, the record is never more than a day behind the face.
SPEED 1.4M/S · AS-BUILT EVERY 10 RINGSWeekly, while the machine is under it
The 1.4 km of surface over the drive is flown on the same ±1.2 cm fix, flight to flight. All 214 settlement markers read from the air, and movement is plotted against the ring the machine was on when it moved.
CORRIDOR 1.4KM · 1.2CM · MARKERS 214On the maintenance shift, out from the gantry
Every frame pins itself to its ring number. A chipped segment, a grout port or the XP-14 breakout at CH 3+790 is found by scrolling the drive, not by booking a possession to walk it.
RINGS 2,140 · AUTO-PINNEDNo. The scan comes off the gantry between shoves: ring 2140 was built at 02:44, scanned at 03:18 and read against the alignment at 03:31 — the machine was already building the next ring.
BUILT 02:44 · SCANNED 03:18 · READ 03:31Within ±8 mm, read per ring rather than per week. The last shove read +6 mm left and −3 mm up at ring 2140, on a 4 mm scan spacing — a drift trend shows on the shift it starts, not forty rings later.
DRIFT ±8MM · RING 2140 · SPACING 4MMThe trough opened behind the shield and flattened at 6 mm. All 214 markers along the corridor read from the weekly flight on a ±1.2 cm fix, and the markers over CH 4+120 held steady at −2 mm.
TROUGH MAX 6MM · CH 4+120 −2MMTwenty-two metres is twelve 1.8 m rings, and the as-built refreshes every ten of them off the trolley at 1.4 m/s. The record advances with the machine — it is never more than ten rings behind the face.
ADVANCE 22M/DAY · AS-BUILT EVERY 10 RINGSNobody walks it — they scroll it. All 2,140 rings are walked in 360 and every frame is pinned to its ring number, so the chipped segment has a frame, a ring and a date instead of a photo on somebody's phone.
RINGS WALKED 2,140 · AUTO-PINNEDXP-14 breaks out at CH 3+790 through rings that carry their scans. The lining either side of the opening is on the record before the cut, so the breakout is set out from measured rings, not nominal ones.
XP-14 · CH 3+790Read overnight on a drive like this one: every gantry scan since the last shift, the trolley's as-built, the corridor flight, 214 marker readings and the alignment at its current revision. Three of the 27 profiles wake up to it.
05:40 · DRIVE 2 · GANTRY
SEQUENCE
Ring 2140 reads +6 mm left and −3 mm up — inside the ±8 mm band, so the next shove is clear and drive 2 holds 22 m a day without waiting on a survey crew.
CITES: GANTRY SCAN 03:18 · ALIGNMENT · RING LOG
07:30 · DRIVE 2 · SCAN SET 04
BIM VS BUILT
The as-built at ring 2140 sits within ±8 mm of design, and XP-14 at CH 3+790 is framed on both sides — the breakout is set out from the cloud, not from the sheet alone.
CITES: MMS RUN · SCAN SET 04 · TU-07 REV G
05:55 · SURFACE · SM ARRAY
SETTLEMENT
Nobody stands in a road to prove the ground is quiet: the trough is flat at 6 mm, the markers over CH 4+120 read −2 mm, and every reading names the ring the machine was on.
CITES: CORRIDOR FLIGHT · MARKERS 214 · SM-09
Overlay capture on the model; drift caught while it's cheap
REV C VS BUILT · Δ FLAGGEDWeekly floor walks auto-pinned to drawings
8 FLOORS/HR · AUTO-PINNEDEvery measurement states the accuracy it was made to
FIX ±1.2CM · SATS 28The site in three dimensions, measurable by anyone who opens it
MESH 40M FACES · DEM 5CMTag an issue on the frame; it lands in the record assigned
TAG→ASSIGN 12SFigures are a specimen record, drawn to the platform's own conventions.
Send us the design alignment and the ring log — we will scan one shift from the gantry and hand you drift against design, ring by ring, before the following push.