diff --git a/src/edu/kit/informatik/Coach.java b/src/edu/kit/informatik/Coach.java
index e8ab561..dfa5ee1 100644
--- a/src/edu/kit/informatik/Coach.java
+++ b/src/edu/kit/informatik/Coach.java
@@ -2,6 +2,9 @@ package edu.kit.informatik;
 
 /**
  * A coach.
+ *
+ * @author Arne Keller
+ * @version 1.0
  */
 public class Coach extends RollingStock {
     private static final String[] PASSENGER_TEXT = new String[] {
diff --git a/src/edu/kit/informatik/CommandLine.java b/src/edu/kit/informatik/CommandLine.java
index 81c6286..f2d9490 100644
--- a/src/edu/kit/informatik/CommandLine.java
+++ b/src/edu/kit/informatik/CommandLine.java
@@ -3,8 +3,14 @@ package edu.kit.informatik;
 import edu.kit.informatik.command.Command;
 import edu.kit.informatik.command.CommandFactory;
 
+/**
+ * Interactive simulation runner, gets user inputs and processes commands specified.
+ *
+ * @author Arne Keller
+ * @version 1.0
+ */
 public class CommandLine {
-    public static final String EXIT = "exit";
+    private static final String EXIT = "exit";
 
     public static void startInteractive() {
         ModelRailwaySimulation simulation = new ModelRailwaySimulation();
diff --git a/src/edu/kit/informatik/ElectricalEngine.java b/src/edu/kit/informatik/ElectricalEngine.java
index 242d024..5776a0e 100644
--- a/src/edu/kit/informatik/ElectricalEngine.java
+++ b/src/edu/kit/informatik/ElectricalEngine.java
@@ -26,7 +26,8 @@ public class ElectricalEngine extends Engine {
      * @param couplingFront whether the engine should have a front coupling
      * @param couplingBack whether the engine should have a back coupling
      */
-    public ElectricalEngine(final String series, final String name, final int length, final boolean couplingFront, final boolean couplingBack) {
+    public ElectricalEngine(final String series, final String name, final int length,
+                            final boolean couplingFront, final boolean couplingBack) {
         super.name = name;
         super.series = series;
         super.length = length;
diff --git a/src/edu/kit/informatik/Engine.java b/src/edu/kit/informatik/Engine.java
index 151a9a2..86d471d 100644
--- a/src/edu/kit/informatik/Engine.java
+++ b/src/edu/kit/informatik/Engine.java
@@ -1,7 +1,13 @@
 package edu.kit.informatik;
 
 public abstract class Engine extends RollingStock {
+    /**
+     * Series/class of this engine.
+     */
     protected String series;
+    /**
+     * Name of this engine.
+     */
     protected String name;
 
     public String getName() {
diff --git a/src/edu/kit/informatik/ModelRailwaySimulation.java b/src/edu/kit/informatik/ModelRailwaySimulation.java
index 2452ae3..94d320c 100644
--- a/src/edu/kit/informatik/ModelRailwaySimulation.java
+++ b/src/edu/kit/informatik/ModelRailwaySimulation.java
@@ -9,6 +9,7 @@ public class ModelRailwaySimulation {
     private List<TrainSet> trainSets = new ArrayList<>();
     private List<Coach> coaches = new ArrayList<>();
     private List<Train> trains = new ArrayList<>();
+
     /**
      * Identifier if success, -1 if fail
      * @param start
diff --git a/src/edu/kit/informatik/RollingStock.java b/src/edu/kit/informatik/RollingStock.java
index 9ddfbe8..0c46988 100644
--- a/src/edu/kit/informatik/RollingStock.java
+++ b/src/edu/kit/informatik/RollingStock.java
@@ -20,6 +20,7 @@ public abstract class RollingStock {
     }
 
     public abstract boolean canCoupleFrontTo(RollingStock rollingStock);
+
     public abstract boolean canCoupleToTrainSetSeries(String series);
 
     public abstract String[] textRepresentation();
diff --git a/src/edu/kit/informatik/Switch.java b/src/edu/kit/informatik/Switch.java
index 0ad600a..42fdaaf 100644
--- a/src/edu/kit/informatik/Switch.java
+++ b/src/edu/kit/informatik/Switch.java
@@ -83,7 +83,8 @@ public final class Switch extends Rail {
         if (selection == null) {
             return String.format("s %d %s -> %s,%s", getIdentifier(), start, end1, end2);
         } else {
-            return String.format("s %d %s -> %s,%s %d", getIdentifier(), start, end1, end2, start.distanceTo(selection));
+            return String.format("s %d %s -> %s,%s %d", getIdentifier(),
+                    start, end1, end2, start.distanceTo(selection));
         }
     }
 
diff --git a/src/edu/kit/informatik/Track.java b/src/edu/kit/informatik/Track.java
index cac5369..c486120 100644
--- a/src/edu/kit/informatik/Track.java
+++ b/src/edu/kit/informatik/Track.java
@@ -2,6 +2,12 @@ package edu.kit.informatik;
 
 import java.util.Objects;
 
+/**
+ * Straight track.
+ *
+ * @author Arne Keller
+ * @version 1.0
+ */
 public final class Track extends Rail {
     public final Point start;
     public final Point end;
diff --git a/src/edu/kit/informatik/Train.java b/src/edu/kit/informatik/Train.java
index a7e88aa..9c22b59 100644
--- a/src/edu/kit/informatik/Train.java
+++ b/src/edu/kit/informatik/Train.java
@@ -3,12 +3,23 @@ package edu.kit.informatik;
 import java.util.ArrayList;
 import java.util.List;
 
+/**
+ * Train.
+ *
+ * @author Arne Keller
+ * @version 1.0
+ */
 public final class Train {
-    private final int identifier; // start at 1
+    private final int identifier;
     private final List<RollingStock> rollingStocks = new ArrayList<>();
     private List<Point> position;
     private Point direction;
 
+    /**
+     * Construct a new train.
+     * @param identifier identifier to use
+     * @param rollingStock initial rolling stock
+     */
     public Train(final int identifier, final RollingStock rollingStock) {
         this.identifier = identifier;
         this.rollingStocks.add(rollingStock);
diff --git a/src/edu/kit/informatik/TrainSet.java b/src/edu/kit/informatik/TrainSet.java
index 120a690..4c571ad 100644
--- a/src/edu/kit/informatik/TrainSet.java
+++ b/src/edu/kit/informatik/TrainSet.java
@@ -1,10 +1,36 @@
 package edu.kit.informatik;
 
+/**
+ * Train set.
+ *
+ * @author Arne Keller
+ * @version 1.0
+ */
 public class TrainSet extends RollingStock {
+    private static final String[] TRAIN_SET_TEXT = new String[] {
+        "         ++         ",
+        "         ||         ",
+        "_________||_________",
+        "|  ___ ___ ___ ___ |",
+        "|  |_| |_| |_| |_| |",
+        "|__________________|",
+        "|__________________|",
+        "   (O)        (O)   "
+    };
+
     private String series;
     private String name;
 
-    public TrainSet(final String series, final String name, final int length, final boolean couplingFront, final boolean couplingBack) {
+    /**
+     * Construct a new train set.
+     * @param series series/class of train set
+     * @param name name of train set
+     * @param length length of train set
+     * @param couplingFront whether the train set should have a front coupling
+     * @param couplingBack whether the train set should have a back coupling
+     */
+    public TrainSet(final String series, final String name, final int length,
+                    final boolean couplingFront, final boolean couplingBack) {
         this.name = name;
         this.series = series;
         super.length = length;
@@ -32,17 +58,6 @@ public class TrainSet extends RollingStock {
         return this.series.equals(series);
     }
 
-    private static final String[] TRAIN_SET_TEXT = new String[] {
-        "         ++         ",
-        "         ||         ",
-        "_________||_________",
-        "|  ___ ___ ___ ___ |",
-        "|  |_| |_| |_| |_| |",
-        "|__________________|",
-        "|__________________|",
-        "   (O)        (O)   "
-    };
-
     @Override
     public String[] textRepresentation() {
         return TRAIN_SET_TEXT;
diff --git a/src/edu/kit/informatik/command/AddTrack.java b/src/edu/kit/informatik/command/AddTrack.java
index 75f7bc2..6cc0928 100644
--- a/src/edu/kit/informatik/command/AddTrack.java
+++ b/src/edu/kit/informatik/command/AddTrack.java
@@ -16,8 +16,8 @@ public class AddTrack extends Command {
 
     /**
      * Construct a new 'add track' command.
-     * @param start
-     * @param end
+     * @param start position of the start of the track
+     * @param end position of the end of the track
      */
     public AddTrack(final Point start, final Point end) {
         this.start = start;
@@ -25,7 +25,7 @@ public class AddTrack extends Command {
     }
 
     @Override
-    public void apply(ModelRailwaySimulation simulation) {
+    public void apply(final ModelRailwaySimulation simulation) {
         if (start.equals(end)) {
             Terminal.printError("track has length 0");
             return;
diff --git a/src/edu/kit/informatik/command/CommandFactory.java b/src/edu/kit/informatik/command/CommandFactory.java
index 98cdc80..eb3c264 100644
--- a/src/edu/kit/informatik/command/CommandFactory.java
+++ b/src/edu/kit/informatik/command/CommandFactory.java
@@ -15,43 +15,43 @@ import java.util.regex.Pattern;
  * @version 1.0
  */
 public class CommandFactory {
-    public static final String ADD_TRACK = "add track";
-    public static final Pattern ADD_TRACK_ARGUMENTS
-            = Pattern.compile(" \\(([+-]?\\d+,[+-]?\\d+)\\) -> \\(([+-]?\\d+,[+-]?\\d+)\\)");
-    public static final String ADD_SWITCH = "add switch";
-    public static final Pattern ADD_SWITCH_ARGUMENTS
-            = Pattern.compile(" \\(([+-]?\\d+,[+-]?\\d+)\\) -> \\(([+-]?\\d+,[+-]?\\d+)\\),\\(([+-]?\\d+,[+-]?\\d+)\\)");
-    public static final String DELETE_TRACK = "delete track";
-    public static final String LIST_TRACKS = "list tracks";
-    public static final String SET_SWITCH = "set switch";
-    public static final Pattern SET_SWITCH_ARGUMENTS
-            = Pattern.compile(" \\+?(\\d+) position \\(([+-]?\\d+,[+-]?\\d+)\\)");
-    public static final String CREATE_ENGINE = "create engine";
-    public static final Pattern CREATE_ENGINE_ARGUMENTS
-            = Pattern.compile(" (electrical|diesel|steam) (\\w+) (\\w+) \\+?(\\d+) (true|false) (true|false)");
-    public static final String LIST_ENGINES = "list engines";
-    public static final String CREATE_COACH = "create coach";
-    public static final Pattern CREATE_COACH_ARGUMENTS
-            = Pattern.compile(" (passenger|freight|special) \\+?(\\d+) (true|false) (true|false)");
-    public static final String LIST_COACHES = "list coaches";
-    public static final String CREATE_TRAIN_SET = "create train-set";
-    public static final Pattern CREATE_TRAIN_SET_ARGUMENTS
-            = Pattern.compile(" (\\w+) (\\w+) \\+?(\\d+) (true|false) (true|false)");
-    public static final String LIST_TRAIN_SETS = "list train-sets";
-    public static final String DELETE_ROLLING_STOCK = "delete rolling stock";
-    public static final Pattern DELETE_ROLLING_STOCK_ARGUMENT
-            = Pattern.compile(" (\\w+(-\\w*)?)");
-    public static final String ADD_TRAIN = "add train";
-    public static final Pattern ADD_TRAIN_ARGUMENTS
-            = Pattern.compile(" \\+?(\\d+) ((\\w+-\\w+)|(W\\+?\\d+))");
-    public static final String DELETE_TRAIN = "delete train";
-    public static final String LIST_TRAINS = "list trains";
-    public static final String SHOW_TRAIN = "show train";
-    public static final String PUT_TRAIN = "put train";
-    public static final Pattern PUT_TRAIN_ARGUMENTS
-            = Pattern.compile(" \\+?(\\d+) at \\(([+-]?\\d+,[+-]?\\d+)\\) in direction ([+-]?\\d+),([+-]?\\d+)");
-    public static final String STEP = "step";
-    public static final String POSITIVE_NUMBER = " \\+?\\d+";
+    private static final String ADD_TRACK = "add track";
+    private static final Pattern ADD_TRACK_ARGUMENTS
+        = Pattern.compile(" \\(([+-]?\\d+,[+-]?\\d+)\\) -> \\(([+-]?\\d+,[+-]?\\d+)\\)");
+    private static final String ADD_SWITCH = "add switch";
+    private static final Pattern ADD_SWITCH_ARGUMENTS
+        = Pattern.compile(" \\(([+-]?\\d+,[+-]?\\d+)\\) -> \\(([+-]?\\d+,[+-]?\\d+)\\),\\(([+-]?\\d+,[+-]?\\d+)\\)");
+    private static final String DELETE_TRACK = "delete track";
+    private static final String LIST_TRACKS = "list tracks";
+    private static final String SET_SWITCH = "set switch";
+    private static final Pattern SET_SWITCH_ARGUMENTS
+        = Pattern.compile(" \\+?(\\d+) position \\(([+-]?\\d+,[+-]?\\d+)\\)");
+    private static final String CREATE_ENGINE = "create engine";
+    private static final Pattern CREATE_ENGINE_ARGUMENTS
+        = Pattern.compile(" (electrical|diesel|steam) (\\w+) (\\w+) \\+?(\\d+) (true|false) (true|false)");
+    private static final String LIST_ENGINES = "list engines";
+    private static final String CREATE_COACH = "create coach";
+    private static final Pattern CREATE_COACH_ARGUMENTS
+        = Pattern.compile(" (passenger|freight|special) \\+?(\\d+) (true|false) (true|false)");
+    private static final String LIST_COACHES = "list coaches";
+    private static final String CREATE_TRAIN_SET = "create train-set";
+    private static final Pattern CREATE_TRAIN_SET_ARGUMENTS
+        = Pattern.compile(" (\\w+) (\\w+) \\+?(\\d+) (true|false) (true|false)");
+    private static final String LIST_TRAIN_SETS = "list train-sets";
+    private static final String DELETE_ROLLING_STOCK = "delete rolling stock";
+    private static final Pattern DELETE_ROLLING_STOCK_ARGUMENT
+        = Pattern.compile(" (\\w+(-\\w*)?)");
+    private static final String ADD_TRAIN = "add train";
+    private static final Pattern ADD_TRAIN_ARGUMENTS
+        = Pattern.compile(" \\+?(\\d+) ((\\w+-\\w+)|(W\\+?\\d+))");
+    private static final String DELETE_TRAIN = "delete train";
+    private static final String LIST_TRAINS = "list trains";
+    private static final String SHOW_TRAIN = "show train";
+    private static final String PUT_TRAIN = "put train";
+    private static final Pattern PUT_TRAIN_ARGUMENTS
+        = Pattern.compile(" \\+?(\\d+) at \\(([+-]?\\d+,[+-]?\\d+)\\) in direction ([+-]?\\d+),([+-]?\\d+)");
+    private static final String STEP = "step";
+    private static final String POSITIVE_NUMBER = " \\+?\\d+";
 
     /**
      * Parse a single line of user input into one command.
diff --git a/src/edu/kit/informatik/command/CreateCoach.java b/src/edu/kit/informatik/command/CreateCoach.java
index 0c632de..888364d 100644
--- a/src/edu/kit/informatik/command/CreateCoach.java
+++ b/src/edu/kit/informatik/command/CreateCoach.java
@@ -23,7 +23,8 @@ public class CreateCoach extends Command {
      * @param couplingFront whether the coach should have a front coupling
      * @param couplingBack whether the coach should have a back coupling
      */
-    public CreateCoach(final CoachType type, final int length, final boolean couplingFront, final boolean couplingBack) {
+    public CreateCoach(final CoachType type, final int length,
+                       final boolean couplingFront, final boolean couplingBack) {
         this.type = type;
         this.length = length;
         this.couplingFront = couplingFront;
diff --git a/src/edu/kit/informatik/command/CreateEngine.java b/src/edu/kit/informatik/command/CreateEngine.java
index 0d410dd..0fa94eb 100644
--- a/src/edu/kit/informatik/command/CreateEngine.java
+++ b/src/edu/kit/informatik/command/CreateEngine.java
@@ -25,7 +25,8 @@ public class CreateEngine extends Command {
      * @param couplingFront whether the new engine should have a front coupling
      * @param couplingBack whether the new engine should have a back coupling
      */
-    public CreateEngine(final EngineType type, final String series, final String name, final int length, final boolean couplingFront, final boolean couplingBack) {
+    public CreateEngine(final EngineType type, final String series, final String name, final int length,
+                        final boolean couplingFront, final boolean couplingBack) {
         this.type = type;
         this.series = series;
         this.name = name;
diff --git a/src/edu/kit/informatik/command/CreateTrainSet.java b/src/edu/kit/informatik/command/CreateTrainSet.java
index 562f149..eefac54 100644
--- a/src/edu/kit/informatik/command/CreateTrainSet.java
+++ b/src/edu/kit/informatik/command/CreateTrainSet.java
@@ -6,6 +6,9 @@ import edu.kit.informatik.TrainSet;
 
 /**
  * Command used to add a new train set.
+ *
+ * @author Arne Keller
+ * @version Arne Keller
  */
 public class CreateTrainSet extends Command {
     private final String series;
@@ -22,7 +25,8 @@ public class CreateTrainSet extends Command {
      * @param couplingFront whether the train set should have a front coupling
      * @param couplingBack whether the train set should have a back coupling
      */
-    public CreateTrainSet(final String series, final String name, final int length, final boolean couplingFront, final boolean couplingBack) {
+    public CreateTrainSet(final String series, final String name, final int length,
+                          final boolean couplingFront, final boolean couplingBack) {
         this.series = series;
         this.name = name;
         this.length = length;
diff --git a/src/edu/kit/informatik/command/DeleteRollingStock.java b/src/edu/kit/informatik/command/DeleteRollingStock.java
index 5f27e0c..98437a7 100644
--- a/src/edu/kit/informatik/command/DeleteRollingStock.java
+++ b/src/edu/kit/informatik/command/DeleteRollingStock.java
@@ -5,6 +5,9 @@ import edu.kit.informatik.Terminal;
 
 /**
  * Command used to delete rolling stock.
+ *
+ * @author Arne Keller
+ * @version 1.0
  */
 public class DeleteRollingStock extends Command {
     private final String id;