Redline as-builts, Basalt Subdivision, MP 87.00 to MP 89.27

The QC checklists and field inspection reports for the cable trough, handholes, foundations, and track and road crossings were compared with plan sheets SC-101 to SC-104, Rev D. 23 of 98 inspected items deviate from the plans. Only those are redlined, numbered 1 to 23 in stationing order, and 12 of them are signed off as passing in the QC records.

Plan sheets SC-101 to SC-104, Rev DBasalt Crossing, Arizona, Sta. 100+00 to 220+004 QC record sets, 98 itemsTolerances per project Special ProvisionsPrepared Nov 5, 2026

Summary

Crossing in a switch

TX-04 lands 25 ft past the switch points

The plans put the under-track crossing at Sta. 136+20, 60 ft before the points of the West Basalt siding switch. The survey attached to the inspection report puts it at Sta. 137+05, under the switch, but the report is signed off because it only checks conduit count and cover (Inspection_Reports_Track_and_Road_Crossings.pdf, p. 4).

Confirm the location with the signal engineer of record before the record drawings are issued.

Wrong revision

Five foundations were built to Rev B

Sig 875, W Basalt 2E, E Basalt 2E, the E Basalt case and Sig 887 are 15 to 25 ft off Rev D along the track, or 1.0 ft off in offset, but match Rev B exactly. The foundation checklist names Rev B in its header row (QC_Checklist_Signal_Foundations.xlsx, Signal and Cases & Gates tabs).

Switch the comparison to Rev B and the five redlines drop out.

Not on the plans

The trough relocation at the culvert is missing from SC-103

From Sta. 174+00 to 182+65 the trough runs on the south side instead of the north side, per the checklist note about the culvert at Sta. 178+00. The relocation added two under-track crossings, TX-07A and TX-07B, and moved HH-108. None of it appears on sheet SC-103.

Add the three items and get written approval for the relocation.

Redlines by plan sheet

Pick a sheet, the categories, and the revision the QC records are compared against. Click a red cloud or a row in the list to see the QC entry next to what the plans show.

Plan sheet

Sheet SC-102

Sta. 130+00 to 160+00 · Rev D, Aug 14, 2026

Plans As-built per QC records Deleted Revision cloud with item number

Offsets are exaggerated about 10 times relative to the stationing scale so lateral moves are visible. The dimensions in the table govern.

Deviations in stationing order

23 deviations in the selected categories, all sheets

QC record vs. plans

Sources and method

Sources

Basalt_Sub_Signal_Comm_Plans_SC-101_to_SC-104_RevD.pdfCurrent plans for the Cinder Cone & Basalt Railroad, Sta. 100+00 to 220+00. Rev D, Aug 14, 2026: signal locations adjusted after the sight-distance review4 sheets, 22 × 34
Basalt_Sub_Signal_Comm_Plans_SC-101_to_SC-104_RevB.pdfPrevious revision, Apr 30, 2026, used where a QC record references it4 sheets, 22 × 34
QC_Checklist_Cable_Trough_MP87-89.xlsxOffset and top of trough per 200-ft segment, with notes, by Basalt Crossing Signal Constructors60 segments
Field_Inspection_Reports_HH-101_to_HH-112.pdfScanned, signed reports with station, type and lid elevation12 pages
QC_Checklist_Signal_Foundations.xlsxSignal, gate and case foundations, Signal and Cases & Gates tabs14 foundations
Inspection_Reports_Track_and_Road_Crossings.pdfReports for 10 crossings on the plans and 2 added, with survey attachment12 pages + attachment
Special_Provisions_Signal_Comm_Cable_Trough.pdfProject special provisions with the construction tolerance table18 pages
ADOT_Encroachment_Permit_SR424.pdfPermit for the conduit crossing under SR 424, minimum cover measured from the subgrade below the pavement section6 pages

Method

Plans. The plan sheets are read as vector PDF. Each handhole, foundation and crossing gets an ID, station, offset, type and elevation. The trough is split into 60 segments of 200 ft.
QC records. The Excel checklists are read directly. The scanned handhole and crossing reports are run through text recognition, and handwritten values are read page by page.
Matching. QC entries are tied to plan items by ID. Entries with no plan item are reported as added items.
Check. Each value is tested against the tolerance table in the Special Provisions and, for SR 424, the ADOT encroachment permit. Differences within tolerance are not redlined.
Redlines. Deviations are drawn on their own layer over the plan sheets and numbered 1 to 23 in stationing order across all four sheets. The result is exported as Basalt_Sub_Redlines_SC-101_to_SC-104.pdf for the record drawings.
Revision. Where a QC record references a revision other than the current one, its values are also compared with that revision.

Assumptions and limitations

Stations along the track are the surveyed stations in the QC records. Coordinates in the detail view are as-built grid values, NAD83(2011) Arizona Central zone (0202), international feet; elevations are NAVD 88.
A trough deviation applies to the length given in the checklist note, otherwise to the whole segment.
QC sign-offs are reported as written. Whether a deviation can be accepted is for the engineer of record and the railroad to decide.
Whether an under-track crossing may sit under a switch is not assessed here; that needs the signal engineer of record.
The 4.0 ft minimum below base of rail is the requirement in the project's Special Provisions. No public standard was found for a railroad's own signal conduit; published railroad requirements for other parties' utilities are deeper, about 4.5–5.5 ft. The railroad's engineering department should confirm the depth, since it decides which crossings are redlined as shallow.
The 3.0 ft cover below subgrade at SR 424 follows the ADOT encroachment permit. ADOT's utility accommodation guideline could not be read in full here; confirm the cover requirement with the ADOT permit office.
Offsets in the sheet view are exaggerated. The dimensions in the tables govern.