diff --git a/specs/port/trios-railway/crates/trios-railway-smoke/src/lib.t27 b/specs/port/trios-railway/crates/trios-railway-smoke/src/lib.t27
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+// trios-railway-smoke — the IGLA RACE pipeline smoke test.
+// Port of gHashTag/trios-railway:crates/trios-railway-smoke/src/lib.rs
+// (at 8b229e9489ee, 200+ lines) — Roadmap Stage 6, goal #4548, target
+// t27c gen-rust.
+//
+// The original validates the full pipeline in under sixty seconds with
+// synthetic data: a deterministic trainer that emits one
+// `step=N val_bpb=F` JSONL line per step (the BPB starts at 3.0 and
+// decays by 0.99 per step; the loss is 80% of the BPB; every line is
+// flushed; the done line reports the last step's BPB, zero with no
+// steps), the seed-agent's line parser, and the local run that parses
+// the outputs back with no database behind it.
+//
+// The stdout printing and flushing are plumbing; the decisions — the
+// configuration defaults, the decay and loss formulas, the step range,
+// the done-line best, the parser's four presence gates with their two
+// markers, and the local run's shape (one line and one sample per step,
+// no DB) — are ported here as pure functions and tested, including the
+// original's own config and parser tests. The powi exponent has no
+// builtin here: the decay is computed by repeated multiplication, one
+// factor per step, exactly what the original's loop unfolds. No
+// transport exists in this port (issue #9796, "Port the decision, not
+// the plumbing").
+
+module port::trios_railway_smoke_lib;
+
+// ---------------------------------------------------------------------------
+// Original lines 18-43: `pub struct SmokeConfig` and its Default.
+// ---------------------------------------------------------------------------
+
+pub struct SmokeConfig {
+    steps: u32,
+    batch: u32,
+    seed: u64,
+    synthetic: bool,
+    timeout_sec: u64,
+}
+
+pub fn SmokeConfig_default() -> SmokeConfig {
+    return SmokeConfig {
+        steps: 1,
+        batch: 2,
+        seed: 42,
+        synthetic: true,
+        timeout_sec: 30,
+    };
+}
+
+// ---------------------------------------------------------------------------
+// Original lines 69-107: `pub fn run_synthetic_trainer(cfg) ->
+// Vec<StepOutput>`. The deterministic trainer: one output per step for
+// steps 1..=cfg.steps, the BPB starting at 3.0 and decaying by 0.99 per
+// step (line 81), the loss at 80% of the BPB (line 82), and the done
+// line reporting the last output's BPB, 0.0 with no outputs (line 102).
+// The growable Vec and the stdout flush are plumbing; the plan this
+// function decides is ported below with the per-step formulas pure.
+// ---------------------------------------------------------------------------
+
+pub struct TrainerPlan {
+    step_count: usize,
+    first_step: u32,
+    base_bpb: f64,
+    decay: f64,
+    loss_factor: f64,
+    done_best: f64,
+}
+
+// Original line 81: `let bpb = base_bpb * decay.powi(step as i32);` —
+// computed by repeated multiplication, one decay factor per step.
+pub fn smoke_bpb(step: u32) -> f64 {
+    var bpb: f64 = 3.0;
+    var i: u32 = 0;
+    while (i < step) {
+        bpb = bpb * 0.99;
+        i += 1;
+    }
+    return bpb;
+}
+
+// Original line 82: `let loss = bpb * 0.8;` — the loss is 80% of the BPB.
+pub fn smoke_loss(bpb: f64) -> f64 {
+    return bpb * 0.8;
+}
+
+// Original lines 100-103: the done line reports the last output's BPB,
+// 0.0 when there are no outputs.
+pub fn trainer_done_best(steps: u32) -> f64 {
+    if (steps == 0) {
+        return 0.0;
+    }
+    return smoke_bpb(steps);
+}
+
+pub fn run_synthetic_trainer(cfg: SmokeConfig) -> TrainerPlan {
+    return TrainerPlan {
+        step_count: cfg.steps,
+        first_step: 1,
+        base_bpb: 3.0,
+        decay: 0.99,
+        loss_factor: 0.8,
+        done_best: trainer_done_best(cfg.steps),
+    };
+}
+
+// ---------------------------------------------------------------------------
+// Original lines 110-126: `pub fn parse_step_line(line) ->
+// Option<(u32, f64)>`. The seed-agent's parser: the line parses exactly
+// when both markers are present AND a parseable token follows each.
+// The string finding and number parsing are plumbing; the four presence
+// gates and the two markers are the decisions.
+// ---------------------------------------------------------------------------
+
+pub fn step_marker() -> str {
+    return "step=";
+}
+
+pub fn bpb_marker() -> str {
+    return "val_bpb=";
+}
+
+pub fn parse_step_line(
+    step_marker_present: bool,
+    step_token_present: bool,
+    bpb_marker_present: bool,
+    bpb_token_present: bool,
+) -> bool {
+    if (!step_marker_present) {
+        return false;
+    }
+    if (!step_token_present) {
+        return false;
+    }
+    if (!bpb_marker_present) {
+        return false;
+    }
+    if (!bpb_token_present) {
+        return false;
+    }
+    return true;
+}
+
+// ---------------------------------------------------------------------------
+// Original lines 130-141: `pub fn run_local(cfg) -> SmokeResult`. The
+// local pipeline: the trainer's outputs parsed back — one JSONL line and
+// one sample per step — with no database behind the run, so the insert
+// verdict is absent.
+// ---------------------------------------------------------------------------
+
+pub struct LocalSmokeView {
+    jsonl_lines: usize,
+    sample_count: usize,
+    db_insert_ok_present: bool,
+}
+
+pub fn run_local(cfg: SmokeConfig) -> LocalSmokeView {
+    return LocalSmokeView {
+        jsonl_lines: cfg.steps,
+        sample_count: cfg.steps,
+        db_insert_ok_present: false,
+    };
+}
+
+// ---------------------------------------------------------------------------
+// Tests: every decision above asserted against values read from the
+// original's own tests (lines 147-186).
+// ---------------------------------------------------------------------------
+
+test config_defaults {
+    const cfg = SmokeConfig_default();
+    assert(cfg.steps == 1);
+    assert(cfg.batch == 2);
+    assert(cfg.seed == 42);
+    assert(cfg.synthetic);
+    assert(cfg.timeout_sec == 30);
+}
+
+test bpb_decays_from_three {
+    assert(smoke_bpb(0) == 3.0);
+    const first = smoke_bpb(1);
+    assert(first > 2.96);
+    assert(first < 2.98);
+    assert(smoke_bpb(2) < smoke_bpb(1));
+    assert(smoke_bpb(3) < smoke_bpb(2));
+}
+
+test loss_is_eighty_percent_of_bpb {
+    const loss = smoke_loss(2.5);
+    assert(loss > 1.999);
+    assert(loss < 2.001);
+    const loss3 = smoke_loss(3.0);
+    assert(loss3 > 2.399);
+    assert(loss3 < 2.401);
+}
+
+test done_best_follows_the_last_step {
+    assert(trainer_done_best(0) == 0.0);
+    assert(trainer_done_best(3) == smoke_bpb(3));
+}
+
+test trainer_plan_shape {
+    const plan = run_synthetic_trainer(SmokeConfig_default());
+    assert(plan.step_count == 1);
+    assert(plan.first_step == 1);
+    assert(plan.base_bpb == 3.0);
+    assert(plan.decay == 0.99);
+    assert(plan.loss_factor == 0.8);
+    const three = run_synthetic_trainer(SmokeConfig { steps: 3, batch: 2, seed: 42, synthetic: true, timeout_sec: 30 });
+    assert(three.step_count == 3);
+}
+
+test parse_gates_and_markers {
+    assert(step_marker() == "step=");
+    assert(bpb_marker() == "val_bpb=");
+    assert(parse_step_line(true, true, true, true));
+    assert(!parse_step_line(false, true, true, true));
+    assert(!parse_step_line(true, false, true, true));
+    assert(!parse_step_line(true, true, false, true));
+    assert(!parse_step_line(true, true, true, false));
+}
+
+test local_view_parses_every_line_without_db {
+    const one = run_local(SmokeConfig_default());
+    assert(one.jsonl_lines == 1);
+    assert(one.sample_count == 1);
+    assert(!one.db_insert_ok_present);
+    const three = run_local(SmokeConfig { steps: 3, batch: 2, seed: 42, synthetic: true, timeout_sec: 30 });
+    assert(three.jsonl_lines == 3);
+    assert(three.sample_count == 3);
+}