diff --git a/src/tunnelbridge_cmd.cpp b/src/tunnelbridge_cmd.cpp
--- a/src/tunnelbridge_cmd.cpp
+++ b/src/tunnelbridge_cmd.cpp
@@ -1680,18 +1680,15 @@ static int GetSlopePixelZ_TunnelBridge(T
 
 		/* On the bridge ramp? */
 		if (ground_vehicle) {
-			int delta;
-
 			if (tileh != SLOPE_FLAT) return z + TILE_HEIGHT;
 
 			switch (dir) {
 				default: NOT_REACHED();
-				case DIAGDIR_NE: delta = (TILE_SIZE - 1 - x) / 2; break;
-				case DIAGDIR_SE: delta = y / 2; break;
-				case DIAGDIR_SW: delta = x / 2; break;
-				case DIAGDIR_NW: delta = (TILE_SIZE - 1 - y) / 2; break;
+				case DIAGDIR_NE: tileh = SLOPE_NE; break;
+				case DIAGDIR_SE: tileh = SLOPE_SE; break;
+				case DIAGDIR_SW: tileh = SLOPE_SW; break;
+				case DIAGDIR_NW: tileh = SLOPE_NW; break;
 			}
-			return z + 1 + delta;
 		}
 	}
 
@@ -1859,6 +1856,29 @@ static void ChangeTileOwner_TunnelBridge
 }
 
 /**
+ * Helper to prepare the ground vehicle when entering a bridge. This get called
+ * when entering the bridge, at the last frame of travel on the bridge head.
+ * Our calling function gets called before UpdateInclination/UpdateZPosition,
+ * which normally controls the Z-coordinate. However, in the wormhole of the
+ * bridge the vehicle is in a strange state so UpdateInclination does not get
+ * called for the wormhole of the bridge and as such the going up/down bits
+ * would remain set. As such, this function clears those. In doing so, the call
+ * to UpdateInclination will not update the Z-coordinate, so that has to be
+ * done here as well.
+ * @param gv The ground vehicle entering the bridge.
+ */
+template <typename T>
+static void PrepareToEnterBridge(T *gv)
+{
+	if (HasBit(gv->gv_flags, GVF_GOINGUP_BIT)) {
+		gv->z_pos++;
+		ClrBit(gv->gv_flags, GVF_GOINGUP_BIT);
+	} else {
+		ClrBit(gv->gv_flags, GVF_GOINGDOWN_BIT);
+	}
+}
+
+/**
  * Frame when the 'enter tunnel' sound should be played. This is the second
  * frame on a tile, so the sound is played shortly after entering the tunnel
  * tile, while the vehicle is still visible.
@@ -1959,17 +1979,14 @@ static VehicleEnterTileStatus VehicleEnt
 				case VEH_TRAIN: {
 					Train *t = Train::From(v);
 					t->track = TRACK_BIT_WORMHOLE;
-					ClrBit(t->gv_flags, GVF_GOINGUP_BIT);
-					ClrBit(t->gv_flags, GVF_GOINGDOWN_BIT);
+					PrepareToEnterBridge(t);
 					break;
 				}
 
 				case VEH_ROAD: {
 					RoadVehicle *rv = RoadVehicle::From(v);
 					rv->state = RVSB_WORMHOLE;
-					/* There are no slopes inside bridges / tunnels. */
-					ClrBit(rv->gv_flags, GVF_GOINGUP_BIT);
-					ClrBit(rv->gv_flags, GVF_GOINGDOWN_BIT);
+					PrepareToEnterBridge(rv);
 					break;
 				}