diff --git a/subsystems/TimingDetector/README.md b/subsystems/TimingDetector/README.md
index 4dafbb2b..d758eb9d 100644
--- a/subsystems/TimingDetector/README.md
+++ b/subsystems/TimingDetector/README.md
@@ -9,9 +9,10 @@ The TimingDetector subsystem implements 330 scintillator bars (3 columns x 110 r
 ## Geometry Tree
 
 ```
-Timing_Detector (Air, 5500×6500×500 mm)
+Timing_Detector (Air, 5500×6500×460 mm)
  └─ 330 × scintillator bars (1400×60×10 mm each)
-     3 columns × 110 rows; z stagger = (row%2)·12 + (col%2)·90 mm
+     3 columns × 110 rows; z stagger = (row%2)·12 + (col%2)·90 mm,
+     bar layer at the front of the container
 ```
 
 Position in world: z = 95902 mm.
diff --git a/subsystems/TimingDetector/include/TimingDetector/TimingDetectorFactory.h b/subsystems/TimingDetector/include/TimingDetector/TimingDetectorFactory.h
index e3b26b6f..2637d205 100644
--- a/subsystems/TimingDetector/include/TimingDetector/TimingDetectorFactory.h
+++ b/subsystems/TimingDetector/include/TimingDetector/TimingDetectorFactory.h
@@ -20,7 +20,7 @@ class SHiPMaterials;
  * "/SHiP/timing_detector/bar_<col>_<row>" names; sensitive-detector assignment
  * is performed downstream by name pattern.
  *
- * Container half-sizes (mm): 2750 × 3250 × 250.
+ * Container half-sizes (mm): 2750 × 3250 × 230.
  * Bar half-sizes (mm):        700 × 30 × 5.
  * Z stagger (mm):             z = (row%2)·12 + (col%2)·90 → levels 0/12/90/102.
  */
@@ -39,10 +39,12 @@ class TimingDetectorFactory {
     SHiPMaterials& m_materials;
     int m_barCount{0};
 
-    // Container dimensions
+    // Container dimensions. The length is the 0.46 m slot of the integration
+    // layout 2026-0.1 (EDMS 3287817 v1.1); the bar layer sits at the front
+    // of the slot, where the CAD model ST1967028_01 has the first bar layer.
     static constexpr double s_containerHalfX = 2750.0 * GeoModelKernelUnits::mm;
     static constexpr double s_containerHalfY = 3250.0 * GeoModelKernelUnits::mm;
-    static constexpr double s_containerHalfZ = 250.0 * GeoModelKernelUnits::mm;
+    static constexpr double s_containerHalfZ = 230.0 * GeoModelKernelUnits::mm;
 
     // Bar dimensions
     static constexpr double s_barHalfX = 700.0 * GeoModelKernelUnits::mm;  // 140 cm full length
diff --git a/subsystems/TimingDetector/src/TimingDetectorFactory.cpp b/subsystems/TimingDetector/src/TimingDetectorFactory.cpp
index 57478055..50978587 100644
--- a/subsystems/TimingDetector/src/TimingDetectorFactory.cpp
+++ b/subsystems/TimingDetector/src/TimingDetectorFactory.cpp
@@ -35,13 +35,15 @@ GeoPhysVol* TimingDetectorFactory::build() {
     // 3 columns × 110 rows = 330 bars. Positions are analytic:
     //   x = (ic - 1) * pitch          → -1300, 0, +1300 mm
     //   y = y0 + ir * step            → -3220 … +3220 mm (step 6440/109)
-    //   z = (ir%2)*12 + (ic%2)*90     → 4 stagger levels: 0, 12, 90, 102 mm
+    //   z = (ir%2)*12 + (ic%2)*90     → 4 stagger levels: 0, 12, 90, 102 mm,
+    //                                   measured from the front face of the slot
     m_barCount = 0;
     for (int ic = 0; ic < s_nColumns; ++ic) {
         const double x = (ic - 1) * s_columnPitchX;
         for (int ir = 0; ir < s_nRows; ++ir) {
             const double y = s_rowY0 + ir * s_rowStepY;
-            const double z = (ir % 2) * s_zStaggerRow + (ic % 2) * s_zStaggerCol;
+            const double z = -s_containerHalfZ + s_barHalfZ + (ir % 2) * s_zStaggerRow +
+                             (ic % 2) * s_zStaggerCol;
             const std::string name =
                 "/SHiP/timing_detector/bar_" + std::to_string(ic) + "_" + std::to_string(ir);
             containerPhys->add(new GeoNameTag(name));