diff --git a/Framework/ProcessSequence/ContinuousProcess.h b/Framework/ProcessSequence/ContinuousProcess.h
index 58d378aa3eb5bdad5f8029555ea8825afa450007..27f6c8fae4cb52e037f7ac128dd5fde161dd5566 100644
--- a/Framework/ProcessSequence/ContinuousProcess.h
+++ b/Framework/ProcessSequence/ContinuousProcess.h
@@ -34,11 +34,11 @@ namespace corsika::process {
     // here starts the interface part
     // -> enforce derived to implement DoContinuous...
     template <typename Particle, typename Track>
-    EProcessReturn DoContinuous(Particle&, Track&) const;
+    EProcessReturn DoContinuous(Particle&, Track const&) const;
 
     // -> enforce derived to implement MaxStepLength...
     template <typename Particle, typename Track>
-    corsika::units::si::LengthType MaxStepLength(Particle& p, Track& track) const;
+    units::si::LengthType MaxStepLength(Particle const& p, Track const& track) const;
   };
 
   // overwrite the default trait class, to mark BaseProcess<T> as useful process