diff --git a/.gitignore b/.gitignore
index d995046f..73131621 100644
--- a/.gitignore
+++ b/.gitignore
@@ -74,4 +74,6 @@ builds/build_*
 builds/*.zip
 builds/deps_*
 
+doc/
+
 CMakeLists.txt.user
diff --git a/AirCoupler.cpp b/AirCoupler.cpp
index 5c6c0b09..32f814fd 100644
--- a/AirCoupler.cpp
+++ b/AirCoupler.cpp
@@ -10,69 +10,77 @@ http://mozilla.org/MPL/2.0/.
 #include "stdafx.h"
 #include "AirCoupler.h"
 
-TAirCoupler::TAirCoupler()
+AirCoupler::AirCoupler()
 {
     Clear();
 }
 
-TAirCoupler::~TAirCoupler()
+AirCoupler::~AirCoupler()
 {
 }
 
-int TAirCoupler::GetStatus()
-{ // zwraca 1, jeśli istnieje model prosty, 2 gdy skośny
-    int x = 0;
-    if (pModelOn)
-        x = 1;
-    if (pModelxOn)
-        x = 2;
-    return x;
+/**
+ * \return 1 when \(straight\) TModel3d \c ModelOn exists
+ * \return 2 when \(slanted\) TModel3d \c ModelxOn exists
+ * \return 0 when neither of them exist
+ */
+int AirCoupler::GetStatus()
+{
+    if (ModelOn) return 1;
+    if (ModelxOn) return 2;
+    return 0;
 }
 
-void TAirCoupler::Clear()
-{ // zerowanie wskaźników
-    pModelOn = NULL;
-    pModelOff = NULL;
-    pModelxOn = NULL;
-    bOn = false;
-    bxOn = false;
+/**
+ * Reset pointers and variables.
+ */
+void AirCoupler::Clear()
+{
+    ModelOn = NULL;
+    ModelOff = NULL;
+    ModelxOn = NULL;
+    On = false;
+    xOn = false;
 }
 
-void TAirCoupler::Init(std::string const &asName, TModel3d *pModel)
-{ // wyszukanie submodeli
-    if (!pModel)
-        return; // nie ma w czym szukać
-    pModelOn = pModel->GetFromName( asName + "_on" ); // połączony na wprost
-    pModelOff = pModel->GetFromName( asName + "_off" ); // odwieszony
-    pModelxOn = pModel->GetFromName( asName + "_xon" ); // połączony na skos
+/**
+ * Looks for submodels in the model and updates pointers.
+ */
+void AirCoupler::Init(std::string const &asName, TModel3d *Model)
+{
+    if (!Model)
+        return;
+    ModelOn = Model->GetFromName(asName + "_on"); // Straight connect.
+    ModelOff = Model->GetFromName(asName + "_off"); // Not connected. Hung up.
+    ModelxOn = Model->GetFromName(asName + "_xon"); // Slanted connect.
 }
-
-void TAirCoupler::Load(cParser *Parser, TModel3d *pModel)
+/**
+ * Gets name of submodel \(from cParser \b *Parser\),
+ * looks for it in the TModel3d \b *Model and update pointers.
+ * If submodel is not found, reset pointers.
+*/
+void AirCoupler::Load(cParser *Parser, TModel3d *Model)
 {
 	std::string name = Parser->getToken<std::string>();
-	if( pModel ) {
-
-		Init( name, pModel );
+    if(Model)
+    {
+		Init(name, Model);
 	}
     else
     {
-        pModelOn = NULL;
-        pModelxOn = NULL;
-        pModelOff = NULL;
+        ModelOn = NULL;
+        ModelxOn = NULL;
+        ModelOff = NULL;
     }
 }
 
-void TAirCoupler::Update()
+// Update submodels visibility.
+void AirCoupler::Update()
 {
-    //  if ((pModelOn!=NULL) && (pModelOn!=NULL))
-    {
-        if (pModelOn)
-            pModelOn->iVisible = bOn;
-        if (pModelOff)
-            pModelOff->iVisible = !(bOn || bxOn);
-        if (pModelxOn)
-            pModelxOn->iVisible = bxOn;
-    }
+    if (ModelOn)
+        ModelOn->iVisible = On;
+    if (ModelOff)
+        ModelOff->iVisible = !(On || xOn);
+    if (ModelxOn)
+        ModelxOn->iVisible = xOn;
 }
-
-//---------------------------------------------------------------------------
diff --git a/AirCoupler.h b/AirCoupler.h
index 8cdebaea..fbb2bd1c 100644
--- a/AirCoupler.h
+++ b/AirCoupler.h
@@ -12,42 +12,40 @@ http://mozilla.org/MPL/2.0/.
 #include "Model3d.h"
 #include "parser.h"
 
-class TAirCoupler
+class AirCoupler
 {
-  private:
-    //    TButtonType eType;
-    TSubModel *pModelOn, *pModelOff, *pModelxOn;
-    bool bOn;
-    bool bxOn;
+private:
+    TSubModel *ModelOn, *ModelOff, *ModelxOn;
+    bool On;
+    bool xOn;
     void Update();
 
-  public:
-    TAirCoupler();
-    ~TAirCoupler();
+public:
+    AirCoupler();
+    ~AirCoupler();
+    ///Reset members.
     void Clear();
-    inline void TurnOn()
-    {
-        bOn = true;
-        bxOn = false;
-        Update();
-    };
-    inline void TurnOff()
-    {
-        bOn = false;
-        bxOn = false;
-        Update();
-    };
-    inline void TurnxOn()
-    {
-        bOn = false;
-        bxOn = true;
-        Update();
-    };
-    //  inline bool Active() { if ((pModelOn)||(pModelOff)) return true; return false;};
+    ///Looks for submodels.
+    void Init(std::string const &asName, TModel3d *Model);
+    ///Loads info about coupler.
+    void Load(cParser *Parser, TModel3d *Model);
     int GetStatus();
-    void Init(std::string const &asName, TModel3d *pModel);
-    void Load(cParser *Parser, TModel3d *pModel);
-    //  bool Render();
+    inline void TurnOn() ///Turns on straight coupler.
+    {
+        On = true;
+        xOn = false;
+        Update();
+    };
+    inline void TurnOff() ///Turns on disconnected coupler.
+    {
+        On = false;
+        xOn = false;
+        Update();
+    };
+    inline void TurnxOn() ///Turns on slanted coupler.
+    {
+        On = false;
+        xOn = true;
+        Update();
+    };
 };
-
-//---------------------------------------------------------------------------
diff --git a/DynObj.h b/DynObj.h
index c8369855..ef706724 100644
--- a/DynObj.h
+++ b/DynObj.h
@@ -266,15 +266,15 @@ public: // modele składowe pojazdu
 
     TButton btCoupler1; // sprzegi
     TButton btCoupler2;
-    TAirCoupler
+    AirCoupler
         btCPneumatic1; // sprzegi powietrzne //yB - zmienione z Button na AirCoupler - krzyzyki
-    TAirCoupler btCPneumatic2;
-    TAirCoupler btCPneumatic1r; // ABu: to zeby nie bylo problemow przy laczeniu wagonow,
-    TAirCoupler btCPneumatic2r; //     jesli beda polaczone sprzegami 1<->1 lub 0<->0
-    TAirCoupler btPneumatic1; // ABu: sprzegi powietrzne zolte
-    TAirCoupler btPneumatic2;
-    TAirCoupler btPneumatic1r; // ABu: analogicznie jak 4 linijki wyzej
-    TAirCoupler btPneumatic2r;
+    AirCoupler btCPneumatic2;
+    AirCoupler btCPneumatic1r; // ABu: to zeby nie bylo problemow przy laczeniu wagonow,
+    AirCoupler btCPneumatic2r; //     jesli beda polaczone sprzegami 1<->1 lub 0<->0
+    AirCoupler btPneumatic1; // ABu: sprzegi powietrzne zolte
+    AirCoupler btPneumatic2;
+    AirCoupler btPneumatic1r; // ABu: analogicznie jak 4 linijki wyzej
+    AirCoupler btPneumatic2r;
 
     TButton btCCtrl1; // sprzegi sterowania
     TButton btCCtrl2;