diff --git a/reconstruction/alert/src/main/java/org/jlab/rec/ahdc/KalmanFilter/KalmanFilter.java b/reconstruction/alert/src/main/java/org/jlab/rec/ahdc/KalmanFilter/KalmanFilter.java
index 3cf9e8a891..7c53a3397b 100644
--- a/reconstruction/alert/src/main/java/org/jlab/rec/ahdc/KalmanFilter/KalmanFilter.java
+++ b/reconstruction/alert/src/main/java/org/jlab/rec/ahdc/KalmanFilter/KalmanFilter.java
@@ -31,12 +31,12 @@
 
 public class KalmanFilter {
 
-    public KalmanFilter(ArrayList<Track> tracks, DataEvent event, boolean IsMC) {propagation(tracks, event, IsMC);}
+    public KalmanFilter(ArrayList<Track> tracks, DataEvent event, final double magfield, boolean IsMC) {propagation(tracks, event, magfield, IsMC);}
 
 	private final int Niter = 10;
 	private final boolean IsVtxDefined = false;
 
-	private void propagation(ArrayList<Track> tracks, DataEvent event, boolean IsMC) {
+	private void propagation(ArrayList<Track> tracks, DataEvent event, final double magfield, boolean IsMC) {
 
 		try {
 			double vz_constraint = 0;
@@ -68,7 +68,6 @@ private void propagation(ArrayList<Track> tracks, DataEvent event, boolean IsMC)
 			}
 
 			// Initialization ---------------------------------------------------------------------
-			final double      magfield          = +50;
 			final PDGParticle proton            = PDGDatabase.getParticleById(2212);
 			final int         numberOfVariables = 6;
 			final double      tesla             = 0.001;
diff --git a/reconstruction/alert/src/main/java/org/jlab/service/ahdc/AHDCEngine.java b/reconstruction/alert/src/main/java/org/jlab/service/ahdc/AHDCEngine.java
index a10bde0985..522f04f534 100644
--- a/reconstruction/alert/src/main/java/org/jlab/service/ahdc/AHDCEngine.java
+++ b/reconstruction/alert/src/main/java/org/jlab/service/ahdc/AHDCEngine.java
@@ -263,7 +263,7 @@ public int compare(Hit a1, Hit a2) {
 
             // VI) Kalman Filter
             // System.out.println("AHDC_Tracks = " + AHDC_Tracks);
-            KalmanFilter kalmanFitter = new KalmanFilter(AHDC_Tracks, event, simulation);
+            KalmanFilter kalmanFitter = new KalmanFilter(AHDC_Tracks, event, magfield, simulation);
             // VII) Write bank
             RecoBankWriter writer = new RecoBankWriter();