# South Tower permanent core transfers

The [South railway corridor follow-up](../path-south-clearance-review/README.md)
records the remaining terminal/steel conflicts and clarifies the removed old tube.
Rail-line checks alone do not establish vehicle clearance.

This pass adds the four permanent core transfers PT507, PT707, PT806 and PT1007 directly to both the main bathtub model and the South Tower detail. Each has two independently registered support columns, two diagonals, a bottom chord and its dimensioned apex bearing plate. Columns 707 and 806 continue from the tops of their plates to concourse. There is no straight basement stem through PT507 or PT1007.

The distinction between construction and completed structure matters: **3-B3-8 expressly identifies TT607 and TT907 as temporary**, and calls for permanent columns when the old PATH tube is removed. Their four N/S construction-support markers are therefore excluded. Ordinary permanent columns 607 and 907 remain. The original R-74 witness pixels, including the temporary positions, remain recorded as source evidence.

All 43 ordinary core display envelopes now continue from concourse to the EL242 lower schedule cut. The lower-lift rows in Book 3 establish that continuity. Their 30 × 30 in sections remain illustrative; they are not transcriptions of the many different column types and plate schedules.

## Primary source

[Original Book 3, Core Columns](https://archive.org/download/WTCI000013L/WTCI-000013-L.PDF), Worthington, Skilling, Helle & Jackson, 1967 transfer drawings, with later revisions in the column schedules. Downloaded source: `sources/WTCI-000013-L.PDF`; SHA-256 is in `source-reading.json`. These are original design drawings, not a survey of the building immediately before September 2001.

| Drawing | PDF page | Use |
|---|---:|---|
| 3-B1-49 | 103 | Transfer member and support sections |
| 3-B3-2 | 132 | PT507: apex 310, chord 286′6″ |
| 3-B3-4 | 134 | PT707: apex 296, chord 286′6″ |
| 3-B3-5 | 135 | PT806: apex 296, chord 286′6″ |
| 3-B3-7 | 137 | PT1007: apex 310, chord 290 |
| 3-B3-8 | 138 | Permanent/temporary distinction and removal sequence |
| 3-B3-9 | 139 | A1: 24 × 4 × 54 in apex plates at 507/1007 |
| 3-B3-11 | 141 | A3: 28 × 6 × 32 in apex plates at 707/806 |
| 3-B3-12 | 142 | Support joint B; remaining fabrication work |
| 3-B3-15 | 145 | Built-up box section 1-1 |
| 3-B3-16 | 146 | Bottom-chord section 2-2 |

The lower-column schedules are PDF55–102, excluding inserted blank PDF58. Do not derive printed drawing numbers by subtracting one constant from the PDF page number. `lower-lift-schedules-1.png` through `-6.png` are labelled by PDF page and column identity. They supersede the exploratory contact strips with incorrect derived drawing suffixes.

## Registration and limits

Longitudinal positions use written distances south from the north perimeter. Transverse positions are the mean X of each N/S pair on R-74. This preserves the independent foundation-plan registration while correcting its roughly one-foot longitudinal raster errors with explicit dimensions. Exact transverse workpoint-to-upper-column-centroid offsets remain unresolved, reaching approximately 1.3 ft on the outer transfer rows. No lateral dogleg or overall scale fit is invented to conceal the difference.

The eight diagonals and eight split supports now use **four scheduled steel plates around a hollow interior**, from 3-B1-49 and 3-B3-15. Plate-1 webs retain the drawn 1½-in setbacks inside the full-D plate ends. Their B × D outer dimensions are unchanged. The 1-1 cut directions in the elevations place B in the north-south truss plane and D transverse to it (east-west). The 54/32-in long dimensions of the apex plates likewise run transverse to the truss; their 24/28-in widths cover the 22/26-in B dimensions of the upper columns. These orientations are tested on the actual meshes. The subsequent [bottom-chord pass](../south-chord-review/README.md) replaces the four combined envelopes with scheduled horizontal plates and outward-facing channel pairs. Channel dimensions use a qualified modern C15x50 reference; historical rolled radii and end bearing fabrication remain unresolved. Inclined members currently terminate as uncoped plate sections at the node coordinates. Detail B (3-B3-12) weld schedule #1 is transcribed for the eight permanent supports; the T1/T2 sizes are inspection data, not modeled weld beads. The four apex plates have sourced dimensions and underside elevations; welds, stiffeners, full joint fabrication, base bearing plates and concrete footing volumes remain incomplete. EL242 is a display cut, not a recovered bearing surface.

The actual main-scene lobby geometry overlaps the 45 South core stems and the two PT507/PT1007 caps. This is a model continuity check, not proof of exact axis alignment or a completed fabricated connection. All 168 perimeter joins retain exact matching footprints.

The preceding core pass exposed **16 rail/component intersection records**. The subsequent [SKA12 rereading](../path-reconciliation/README.md) reduces the production-mesh result to zero with every structural workpoint and outer envelope retained. The rail datum remains projected at constant EL246′6″; exact track setting-out, vehicle clearances, switches and approach grades are unresolved. Interior floor beams, slab openings and surrounding plaza supports also remain unfinished.

## Reproduce and verify

Run from the original workspace with the source PDF available:

```
.venv/bin/python tools/review_south_core.py
.venv/bin/python tools/build_sublevels.py
.venv/bin/python tools/build_slurry_wall.py
.venv/bin/python tools/build_structural_details.py
node tools/check_south_core_transfers.mjs
node tools/check_south_basement_frame.mjs
node tools/check_tower_sublevel_integration.mjs
node tools/check_slurry_wall.mjs
node tools/check_foundation_details.mjs
.venv/bin/python tools/check_sublevels.py
```

The core test uses independent written-dimension witnesses and production Three meshes: four trusses, eight legs, eight diagonals, four chords, four caps, 20 open-space rays and 16 solid-member rays, plus 16 longitudinal hollow-bore rays and 64 individual-plate rays. It checks the absence of temporary supports and false straight stems through the permanent transfers. The existing exterior test retains 3,133 opening rays, 26 column witnesses and five distinctive brace witnesses. No browser/GPU QA was performed.