diff --git a/Processes/ObservationPlane/ObservationPlane.cc b/Processes/ObservationPlane/ObservationPlane.cc
index 27bed61acc8582b54f411051137ad748706128c4..036bbcacfaf32379ba9633035ce1d5ea7d7cf19a 100644
--- a/Processes/ObservationPlane/ObservationPlane.cc
+++ b/Processes/ObservationPlane/ObservationPlane.cc
@@ -69,25 +69,26 @@ LengthType ObservationPlane::MaxStepLength(setup::Stack::ParticleType const& vPa
   }
   auto const* currentLogicalVolumeNode = vParticle.GetNode();
   auto magneticfield = currentLogicalVolumeNode->GetModelProperties().GetMagneticField(vParticle.GetPosition());
-  geometry::Vector<SpeedType::dimension_type> const velocity = trajectory.GetV0();
+  auto direction = trajectory.GetV0().normalized();
   
-  if (chargeNumber != 0 && plane_.GetNormal().dot(velocity.cross(magneticfield)) * 1_s / 1_m / 1_T > 0.0001) {
+  if (chargeNumber != 0 && plane_.GetNormal().dot(trajectory.GetV0().cross(magneticfield)) * 1_s / 1_m / 1_T > 1e-6) {
     auto const* currentLogicalVolumeNode = vParticle.GetNode();
     auto magneticfield = currentLogicalVolumeNode->GetModelProperties().GetMagneticField(vParticle.GetPosition());
-    auto k = chargeNumber * corsika::units::constants::cSquared * 1_eV / 
-            (velocity.GetSquaredNorm() * vParticle.GetEnergy() * 1_V); 
+    auto k = chargeNumber * corsika::units::constants::c * 1_eV / (vParticle.GetMomentum().norm() * 1_V);
+    
     LengthType MaxStepLength1 = 
-      ( sqrt(velocity.dot(plane_.GetNormal()) * velocity.dot(plane_.GetNormal()) / velocity.GetSquaredNorm() - 
+      ( sqrt(direction.dot(plane_.GetNormal()) * direction.dot(plane_.GetNormal()) - 
       (plane_.GetNormal().dot(trajectory.GetR0() - plane_.GetCenter()) * 
-      plane_.GetNormal().dot(velocity.cross(magneticfield)) * 2 * k)) - 
-      velocity.dot(plane_.GetNormal()) / velocity.GetNorm() ) / 
-      (plane_.GetNormal().dot(velocity.cross(magneticfield)) * k);
+      plane_.GetNormal().dot(direction.cross(magneticfield)) * 2 * k)) - 
+      direction.dot(plane_.GetNormal()) / direction.GetNorm() ) / 
+      (plane_.GetNormal().dot(direction.cross(magneticfield)) * k);
+      
     LengthType MaxStepLength2 = 
-      ( - sqrt(velocity.dot(plane_.GetNormal()) * velocity.dot(plane_.GetNormal()) / velocity.GetSquaredNorm() - 
+      ( - sqrt(direction.dot(plane_.GetNormal()) * direction.dot(plane_.GetNormal()) - 
       (plane_.GetNormal().dot(trajectory.GetR0() - plane_.GetCenter()) * 
-      plane_.GetNormal().dot(velocity.cross(magneticfield)) * 2 * k)) - 
-      velocity.dot(plane_.GetNormal()) / velocity.GetNorm() ) / 
-      (plane_.GetNormal().dot(velocity.cross(magneticfield)) * k);
+      plane_.GetNormal().dot(direction.cross(magneticfield)) * 2 * k)) - 
+      direction.dot(plane_.GetNormal()) / direction.GetNorm() ) / 
+      (plane_.GetNormal().dot(direction.cross(magneticfield)) * k);
       
     if (MaxStepLength1 <= 0_m && MaxStepLength2 <= 0_m) {
       return std::numeric_limits<double>::infinity() * 1_m;
@@ -108,6 +109,7 @@ LengthType ObservationPlane::MaxStepLength(setup::Stack::ParticleType const& vPa
   }
 
   auto const pointOfIntersection = trajectory.GetPosition(timeOfIntersection);
+  std::cout << " obs plane non b-field " << std::endl;
   return (trajectory.GetR0() - pointOfIntersection).norm() * 1.0001;
 }
 
diff --git a/Processes/TrackingLine/TrackingLine.h b/Processes/TrackingLine/TrackingLine.h
index 10f848089e0c032b77086177c195dc97897e77b9..b1906de6962dcbb3ead080f5d796c267229d548c 100644
--- a/Processes/TrackingLine/TrackingLine.h
+++ b/Processes/TrackingLine/TrackingLine.h
@@ -293,7 +293,7 @@ namespace corsika::process {
           
           // creating Line with magnetic field
           if (chargeNumber != 0) {
-            auto k = chargeNumber * corsika::units::constants::cSquared * 1_eV / (velocity.norm() * p.GetEnergy() * 1_V);
+            auto k = chargeNumber * corsika::units::constants::c * 1_eV / (p.GetMomentum().norm() * 1_V);
             geometry::Vector<dimensionless_d> const directionBefore = velocity.normalized();
           	// determine steplength to next volume
             double a = ((directionBefore.cross(magneticfield)).dot(currentPosition - sphere.GetCenter()) * k + 1) * 4 / 
@@ -352,7 +352,7 @@ namespace corsika::process {
           
           // creating Line with magnetic field
           if (chargeNumber != 0) {
-            auto k = chargeNumber * corsika::units::constants::cSquared * 1_eV / (velocity.norm() * p.GetEnergy() * 1_V);
+            auto k = chargeNumber * corsika::units::constants::c * 1_eV / (p.GetMomentum().norm() * 1_V);
             geometry::Vector<dimensionless_d> const directionBefore = velocity.normalized();
           	// determine steplength to next volume
             double a = ((directionBefore.cross(magneticfield)).dot(currentPosition - sphere.GetCenter()) * k + 1) * 4 /