Promethium Line · Pipe Bridge with Walkway & Turning Valve Wheel · 28–32 mm Grimdark Wargaming Terrain

### The first span of the line

A-01 is where the Promethium Line starts: a raised promethium main on two riveted portals, with a grated maintenance walkway at 3″, armoured parapets, a ladder, sandbags, drums and a cracked pipe dripping into an oil pool. The red handwheel on top really turns, and its indicator disc shows OPEN or SHUT for the terrain action IGNITE.

### Features

- Footprint 6″ × 4″ (152.4 × 101.6 mm), the base plate is the terrain area
- Walkway at 76.2 mm = 3″, 46.4 mm wide: a 40 mm base stands fully on it
- 69.6 mm clear passage under the walkway
- Armoured parapets (24 mm) with vision slits, 18 mm railings, ladder with 8 mm rung pitch
- Loose handwheel on a spigot with an OPEN / SHUT indicator disc
- Pipe Ø 26 mm with a Ø 44 mm system flange flush at both plate edges, pipe axis 89.2 mm above the table
- Rules card pocket under the base plate
- Sand relief base with feathered rim, hazard stripes and an oil pool recess

### Game use

Rules for Warhammer 40,000, 11th edition. Unofficial fan-made terrain. Not affiliated with or endorsed by Games Workshop. Warhammer 40,000 is a trademark of Games Workshop Ltd.

- Category: Light (suggested, agree before the game). All models can move through it.
- Levels: 3″ walkway, an upper level with Plunging Fire.
- Objective piece: no.
- Terrain action IGNITE: at the start of your Shooting phase, one unit within 6″ of the oil pool can give up its shooting and charge for the turn to turn the wheel to OPEN. Until the end of the next turn, models in this pipe bridge do not count as within a terrain area for Benefit of Cover and Hidden. This hits the models of both players. Cover from other terrain still counts. Then the wheel goes back to SHUT.
- Set-wide frame: terrain actions are optional. Each player can start 1 terrain action per battle round, across all modules and copies. Effects do not stack.

### Print settings

- PETG, 0.4 mm nozzle, 0.2 mm layers (first layer 0.2 mm)
- 3 perimeters, 4 bottom / 5 top layers, 15 % gyroid, 240 °C nozzle / 80 °C bed (your filament maker's values take precedence)
- No supports, no brim. Every part fits a 220 × 220 mm bed and is already in print orientation.
- Turn on elephant-foot compensation (0.1–0.15 mm): the pin sockets and magnet pockets of the flanges sit on the bed.
- If the 76 mm tall pipe halves (plate D) lose adhesion, add a 5 mm brim.
- 19 printed parts on 4 plates, plus the flange coupon (plate T) and an optional tolerance comb (plate T2)

Print time and filament (PrusaSlicer 2.9.6 estimate, generic 220 mm bed slinger, heat-up not included, faster printers need considerably less):

- T · Flange coupon, print first: 0 h 28 min · 4 g
- T2 · Tolerance comb, optional: 0 h 16 min · 2 g
- A · Base plate + card frame: 3 h 52 min · 38 g
- B · Walkway, 2 railings, ladder: 3 h 15 min · 35 g
- C · 2 portals, 3 drums, valve parts, 3 pins: 2 h 33 min · 27 g
- D · Pipe, 2 halves upright: 3 h 46 min · 46 g
- Total A–D: 13 h 26 min · 145 g

### What else you need

- 4 magnets, 5 × 2 mm discs (plus 4 if you fit them in the coupon)
- 8 pieces of 1.75 mm filament, about 5 mm each, as dowels
- Super glue or two-part epoxy

### Assembly highlights

- Print the coupon first. The pin should go in with light pressure and stay in, and both strips should sit flat against each other. The comb shows socket sizes 5.30 to 5.50 mm side by side. If the fit is off, change SOCKET in the source and rebuild.
- Magnet polarity, the same on every flange of the set: look at the flange face with the notch on the rim at the top. Left magnet north pole out, right magnet south pole out. Mark the magnets with a felt pen before gluing.
- The portals push into concrete footings, the walkway locks onto the portal beams, railings and ladder are pinned with filament dowels.
- Leave the handwheel loose on its spigot so it turns. Start of the battle: SHUT.
- Step-by-step instructions with all parts are in BUILD_GUIDE_A.pdf.

### Works with the rest of the set

Promethium Line is a coherent terrain set in ten modules with one story. The mountain is the promethium source, drill station D taps it, and the pipeline H carries it past pipe bridge A and buffer tank B to the refinery with tower E and the bombed tower turned drill rig F. Loading yard G closes the chain. Craters K, the tanker wreck C and field defences J show the fight for it.

Every pipe flange in the set fits every other flange: Ø 44 mm, a square system pin and two 5 × 2 mm magnets. Pipe bridge A sits on the 89.2 mm high line with B, D, E and F. The pipeline riser H12 brings the 28.0 mm ground line up to it. See the Promethium Line collection for all modules.

### Files

- Model files: all single STLs in print orientation, plus one PrusaSlicer 3MF project per print plate, named job_<plate>_….3mf (T, T2, A, B, C, D). There is no G-code. Slice the 3MF projects with your own printer profile.
- Other files:
- rules_card_A.pdf: the module's rules card, 85 × 54 mm, for the card pocket
- TABLE_RULES_card.pdf: one card for the whole table (Core Rules reminder, objectives, terrain actions), two sides
- BUILD_GUIDE_A.pdf: parts list, plates, magnet polarity and step-by-step assembly
- RULES.pdf: all set rules in full, with Core Rules references and the balance maths
- source_A.zip: the parametric source code, to change tolerances and rebuild every STL
- Print all cards at 100 % (no page scaling). The Table Rules card has two pages: cut them out and glue them back to back.

### How it was made

Designed with AI assistance as parametric Python CAD code (build123d / manifold3d) and checked by automated tests: watertight meshes, overhangs of at most 45°, bridge lengths, collision checks of the full assembly and a PrusaSlicer run for every plate. It has not been test-printed yet. The fits are designed, not proven on a real printer, so print the flange coupon first. Makes and feedback are very welcome.