diff --git a/src/edu/kit/informatik/command/AddSwitch.java b/src/edu/kit/informatik/command/AddSwitch.java
index dbe5f45..c72ddbd 100644
--- a/src/edu/kit/informatik/command/AddSwitch.java
+++ b/src/edu/kit/informatik/command/AddSwitch.java
@@ -10,7 +10,7 @@ import edu.kit.informatik.Terminal;
  * @author Arne Keller
  * @version 1.0
  */
-public class AddSwitch extends Command {
+public class AddSwitch implements Command {
     private final Point start;
     private final Point end1;
     private final Point end2;
diff --git a/src/edu/kit/informatik/command/AddTrack.java b/src/edu/kit/informatik/command/AddTrack.java
index 6cc0928..f4e70a6 100644
--- a/src/edu/kit/informatik/command/AddTrack.java
+++ b/src/edu/kit/informatik/command/AddTrack.java
@@ -10,7 +10,7 @@ import edu.kit.informatik.Terminal;
  * @author Arne Keller
  * @version 1.0
  */
-public class AddTrack extends Command {
+public class AddTrack implements Command {
     private Point start;
     private Point end;
 
diff --git a/src/edu/kit/informatik/command/AddTrain.java b/src/edu/kit/informatik/command/AddTrain.java
index 8704d3f..9103b5e 100644
--- a/src/edu/kit/informatik/command/AddTrain.java
+++ b/src/edu/kit/informatik/command/AddTrain.java
@@ -10,7 +10,7 @@ import edu.kit.informatik.Terminal;
  * @author Arne Keller
  * @version 1.0
  */
-public class AddTrain extends Command {
+public class AddTrain implements Command {
     private final int trainId;
     private final String rollingStockId;
 
diff --git a/src/edu/kit/informatik/command/Command.java b/src/edu/kit/informatik/command/Command.java
index 231b1c7..9006d11 100644
--- a/src/edu/kit/informatik/command/Command.java
+++ b/src/edu/kit/informatik/command/Command.java
@@ -3,12 +3,12 @@ package edu.kit.informatik.command;
 import edu.kit.informatik.ModelRailwaySimulation;
 
 /**
- * Generic command that can be applied to a simulation.
- * Commands are implemented as separate classes to avoid god enums :)
+ * Command that can be applied to a simulation.
+ * Commands are implemented as separate classes to avoid a god enum :)
  *
  * @author Arne Keller
  * @version 1.0
  */
-public abstract class Command {
-    public abstract void apply(ModelRailwaySimulation simulation);
+public interface Command {
+    void apply(ModelRailwaySimulation simulation);
 }
diff --git a/src/edu/kit/informatik/command/CreateCoach.java b/src/edu/kit/informatik/command/CreateCoach.java
index 888364d..ca4690c 100644
--- a/src/edu/kit/informatik/command/CreateCoach.java
+++ b/src/edu/kit/informatik/command/CreateCoach.java
@@ -10,7 +10,7 @@ import edu.kit.informatik.Terminal;
  * @author Arne Keller
  * @version 1.0
  */
-public class CreateCoach extends Command {
+public class CreateCoach implements Command {
     private final CoachType type;
     private final int length;
     private final boolean couplingFront;
diff --git a/src/edu/kit/informatik/command/CreateEngine.java b/src/edu/kit/informatik/command/CreateEngine.java
index 0fa94eb..863e551 100644
--- a/src/edu/kit/informatik/command/CreateEngine.java
+++ b/src/edu/kit/informatik/command/CreateEngine.java
@@ -8,7 +8,7 @@ import edu.kit.informatik.*;
  * @author Arne Keller
  * @version 1.0
  */
-public class CreateEngine extends Command {
+public class CreateEngine implements Command {
     private final EngineType type;
     private final String series;
     private final String name;
diff --git a/src/edu/kit/informatik/command/CreateTrainSet.java b/src/edu/kit/informatik/command/CreateTrainSet.java
index eefac54..0dc251c 100644
--- a/src/edu/kit/informatik/command/CreateTrainSet.java
+++ b/src/edu/kit/informatik/command/CreateTrainSet.java
@@ -10,7 +10,7 @@ import edu.kit.informatik.TrainSet;
  * @author Arne Keller
  * @version Arne Keller
  */
-public class CreateTrainSet extends Command {
+public class CreateTrainSet implements Command {
     private final String series;
     private final String name;
     private final int length;
diff --git a/src/edu/kit/informatik/command/DeleteRollingStock.java b/src/edu/kit/informatik/command/DeleteRollingStock.java
index 98437a7..21cd31a 100644
--- a/src/edu/kit/informatik/command/DeleteRollingStock.java
+++ b/src/edu/kit/informatik/command/DeleteRollingStock.java
@@ -9,7 +9,7 @@ import edu.kit.informatik.Terminal;
  * @author Arne Keller
  * @version 1.0
  */
-public class DeleteRollingStock extends Command {
+public class DeleteRollingStock implements Command {
     private final String id;
 
     /**
diff --git a/src/edu/kit/informatik/command/DeleteTrack.java b/src/edu/kit/informatik/command/DeleteTrack.java
index a5b246f..db6c233 100644
--- a/src/edu/kit/informatik/command/DeleteTrack.java
+++ b/src/edu/kit/informatik/command/DeleteTrack.java
@@ -9,7 +9,7 @@ import edu.kit.informatik.Terminal;
  * @author Arne Keller
  * @version 1.0
  */
-public class DeleteTrack extends Command {
+public class DeleteTrack implements Command {
     private final int id;
 
     /**
diff --git a/src/edu/kit/informatik/command/DeleteTrain.java b/src/edu/kit/informatik/command/DeleteTrain.java
index e45d3aa..dfb9d7d 100644
--- a/src/edu/kit/informatik/command/DeleteTrain.java
+++ b/src/edu/kit/informatik/command/DeleteTrain.java
@@ -9,7 +9,7 @@ import edu.kit.informatik.Terminal;
  * @author Arne Keller
  * @version 1.0
  */
-public class DeleteTrain extends Command {
+public class DeleteTrain implements Command {
     private final int id;
 
     /**
diff --git a/src/edu/kit/informatik/command/ListCoaches.java b/src/edu/kit/informatik/command/ListCoaches.java
index f13d8f9..915f215 100644
--- a/src/edu/kit/informatik/command/ListCoaches.java
+++ b/src/edu/kit/informatik/command/ListCoaches.java
@@ -8,7 +8,7 @@ import edu.kit.informatik.ModelRailwaySimulation;
  * @author Arne Keller
  * @version 1.0
  */
-public class ListCoaches extends Command {
+public class ListCoaches implements Command {
     @Override
     public void apply(final ModelRailwaySimulation simulation) {
         simulation.printCoaches();
diff --git a/src/edu/kit/informatik/command/ListEngines.java b/src/edu/kit/informatik/command/ListEngines.java
index 302594b..b6b127f 100644
--- a/src/edu/kit/informatik/command/ListEngines.java
+++ b/src/edu/kit/informatik/command/ListEngines.java
@@ -8,7 +8,7 @@ import edu.kit.informatik.ModelRailwaySimulation;
  * @author Arne Keller
  * @version 1.0
  */
-public class ListEngines extends Command {
+public class ListEngines implements Command {
     @Override
     public void apply(final ModelRailwaySimulation simulation) {
         simulation.printEngines();
diff --git a/src/edu/kit/informatik/command/ListTracks.java b/src/edu/kit/informatik/command/ListTracks.java
index 98dbff9..5d00452 100644
--- a/src/edu/kit/informatik/command/ListTracks.java
+++ b/src/edu/kit/informatik/command/ListTracks.java
@@ -8,7 +8,7 @@ import edu.kit.informatik.ModelRailwaySimulation;
  * @author Arne Keller
  * @version 1.0
  */
-public class ListTracks extends Command {
+public class ListTracks implements Command {
     @Override
     public void apply(final ModelRailwaySimulation simulation) {
         simulation.printTracks();
diff --git a/src/edu/kit/informatik/command/ListTrainSets.java b/src/edu/kit/informatik/command/ListTrainSets.java
index 9cb6783..6caa4d4 100644
--- a/src/edu/kit/informatik/command/ListTrainSets.java
+++ b/src/edu/kit/informatik/command/ListTrainSets.java
@@ -8,7 +8,7 @@ import edu.kit.informatik.ModelRailwaySimulation;
  * @author Arne Keller
  * @version 1.0
  */
-public class ListTrainSets extends Command {
+public class ListTrainSets implements Command {
     @Override
     public void apply(final ModelRailwaySimulation simulation) {
         simulation.printTrainSets();
diff --git a/src/edu/kit/informatik/command/ListTrains.java b/src/edu/kit/informatik/command/ListTrains.java
index 8bd08b5..548bbd3 100644
--- a/src/edu/kit/informatik/command/ListTrains.java
+++ b/src/edu/kit/informatik/command/ListTrains.java
@@ -8,7 +8,7 @@ import edu.kit.informatik.ModelRailwaySimulation;
  * @author Arne Keller
  * @version 1.0
  */
-public class ListTrains extends Command {
+public class ListTrains implements Command {
     @Override
     public void apply(final ModelRailwaySimulation simulation) {
         simulation.printTrains();
diff --git a/src/edu/kit/informatik/command/PutTrain.java b/src/edu/kit/informatik/command/PutTrain.java
index f0be681..80eec34 100644
--- a/src/edu/kit/informatik/command/PutTrain.java
+++ b/src/edu/kit/informatik/command/PutTrain.java
@@ -10,7 +10,7 @@ import edu.kit.informatik.Terminal;
  * @author Arne Keller
  * @version 1.0
  */
-public class PutTrain extends Command {
+public class PutTrain implements Command {
     private final int id;
     private final Point point;
     private final int x;
diff --git a/src/edu/kit/informatik/command/SetSwitch.java b/src/edu/kit/informatik/command/SetSwitch.java
index 1734724..b6f5c30 100644
--- a/src/edu/kit/informatik/command/SetSwitch.java
+++ b/src/edu/kit/informatik/command/SetSwitch.java
@@ -10,7 +10,7 @@ import edu.kit.informatik.Terminal;
  * @author Arne Keller
  * @version 1.0
  */
-public class SetSwitch extends Command {
+public class SetSwitch implements Command {
     private final int id;
     private final Point point;
 
diff --git a/src/edu/kit/informatik/command/ShowTrain.java b/src/edu/kit/informatik/command/ShowTrain.java
index e46b74f..affd267 100644
--- a/src/edu/kit/informatik/command/ShowTrain.java
+++ b/src/edu/kit/informatik/command/ShowTrain.java
@@ -8,7 +8,7 @@ import edu.kit.informatik.ModelRailwaySimulation;
  * @author Arne Keller
  * @version 1.0
  */
-public class ShowTrain extends Command {
+public class ShowTrain implements Command {
     private final int id;
 
     /**
diff --git a/src/edu/kit/informatik/command/Step.java b/src/edu/kit/informatik/command/Step.java
index b40c438..db9e5cb 100644
--- a/src/edu/kit/informatik/command/Step.java
+++ b/src/edu/kit/informatik/command/Step.java
@@ -8,7 +8,7 @@ import edu.kit.informatik.ModelRailwaySimulation;
  * @author Arne Keller
  * @version 1.0
  */
-public class Step extends Command {
+public class Step implements Command {
     private final short speed;
 
     /**