diff --git a/Driver.cpp b/Driver.cpp
index cc82fa2b..be287014 100644
--- a/Driver.cpp
+++ b/Driver.cpp
@@ -7622,7 +7622,7 @@ void TController::control_tractive_force() {
     auto const velocity { DirectionalVel() };
     // jeśli przyspieszenie pojazdu jest mniejsze niż żądane oraz...
     if( ( AccDesired > EU07_AI_NOACCELERATION ) // don't add power if not asked for actual speed-up
-     && ( AccDesired - AbsAccS > 0.05 )
+     && ( AbsAccS < AccDesired /* - 0.05 */ )
      && ( false == TestFlag( iDrivigFlags, movePress ) ) ) {
         // ...jeśli prędkość w kierunku czoła jest mniejsza od dozwolonej o margines...
         if( velocity < (
@@ -7652,7 +7652,7 @@ void TController::control_tractive_force() {
         else if( ( velocity > VelDesired + SpeedCtrlMargin)
               || ( fAccGravity < -0.01 ?
                         AccDesired < 0.0 :
-                        (AbsAccS > AccDesired + 0.05) )
+                        ( AbsAccS > AccDesired + 0.05 ) )
                || ( IsAnyCouplerStretched ) ) {
                 // jak za bardzo przyspiesza albo prędkość przekroczona
 				// dodany wyjatek na "pelna w przod"
@@ -7817,11 +7817,12 @@ void TController::control_releaser() {
     if( mvOccupied->BrakeSystem != TBrakeSystem::Pneumatic ) { return; }
 
     auto const hasreleaser {
-        ( mvOccupied->BrakeHandle == TBrakeHandle::FV4a )
-     || ( mvOccupied->BrakeHandle == TBrakeHandle::MHZ_6P )
-     || ( mvOccupied->BrakeHandle == TBrakeHandle::MHZ_K5P )
-     || ( mvOccupied->BrakeHandle == TBrakeHandle::MHZ_K8P )
-     || ( mvOccupied->BrakeHandle == TBrakeHandle::M394 ) };
+        ( false == ( is_dmu() || is_emu() ) ) // TODO: a more refined test than rejecting these types wholesale
+     && ( ( mvOccupied->BrakeHandle == TBrakeHandle::FV4a )
+       || ( mvOccupied->BrakeHandle == TBrakeHandle::MHZ_6P )
+       || ( mvOccupied->BrakeHandle == TBrakeHandle::MHZ_K5P )
+       || ( mvOccupied->BrakeHandle == TBrakeHandle::MHZ_K8P )
+       || ( mvOccupied->BrakeHandle == TBrakeHandle::M394 ) ) };
     
     if( false == hasreleaser ) { return; }
 
diff --git a/DynObj.cpp b/DynObj.cpp
index af41a8f1..ca094e5c 100644
--- a/DynObj.cpp
+++ b/DynObj.cpp
@@ -4109,17 +4109,20 @@ void TDynamicObject::RenderSounds() {
     }
 
     // heater sound
-    if( ( true == MoverParameters->Heating )
-     && ( std::abs( MoverParameters->enrot ) > 0.01 ) ) {
-        // TBD: check whether heating should depend on 'engine rotations' for electric vehicles
-        sHeater
-            .pitch( true == sHeater.is_combined() ?
+    {
+        auto const isdieselenginepowered { ( MoverParameters->EngineType == TEngineType::DieselElectric ) || ( MoverParameters->EngineType == TEngineType::DieselEngine ) };
+        if( ( true == MoverParameters->Heating )
+         && ( ( false == isdieselenginepowered )
+           || ( std::abs( MoverParameters->enrot ) > 0.01 ) ) ) {
+            sHeater
+                .pitch( true == sHeater.is_combined() ?
                     std::abs( MoverParameters->enrot ) * 60.f * 0.01f :
                     1.f )
-            .play( sound_flags::exclusive | sound_flags::looping );
-    }
-    else {
-        sHeater.stop();
+                .play( sound_flags::exclusive | sound_flags::looping );
+        }
+        else {
+            sHeater.stop();
+        }
     }
 
     // battery sound
@@ -4338,6 +4341,11 @@ void TDynamicObject::RenderSounds() {
                 m_pasystem.announcement = m_pasystem.announcement_queue.front();
                 m_pasystem.announcement.owner( this );
                 m_pasystem.announcement.range( 0.5 * MoverParameters->Dim.L * -1 );
+                if( m_pasystem.soundproofing ) {
+                    if( !m_pasystem.announcement.soundproofing() ) {
+                        m_pasystem.announcement.soundproofing() = m_pasystem.soundproofing;
+                    }
+                }
                 m_pasystem.announcement.play();
                 m_pasystem.announcement_queue.pop_front();
             }
@@ -5958,7 +5966,6 @@ void TDynamicObject::LoadMMediaFile( std::string const &TypeName, std::string co
 					// announcement sounds
                     // content provided as "key: value" pairs together enclosed in "{}"
                     // value can be optionally set of values enclosed in "[]" in which case one value will be picked randomly
-                    std::array<sound_source, static_cast<int>( announcement_t::end )> announcementsounds;
                     std::unordered_map<std::string, announcement_t> const announcements = {
                         { "near_stop:", announcement_t::approaching },
                         { "stop:", announcement_t::current },
@@ -5968,23 +5975,50 @@ void TDynamicObject::LoadMMediaFile( std::string const &TypeName, std::string co
                     while( ( ( token = parser.getToken<std::string>() ) != "" )
                         && ( token != "}" ) ) {
                         if( token.back() == ':' ) {
+
+                            if( token == "soundproofing:" ) {
+                                // custom soundproofing in format [ p1, p2, p3, p4, p5, p6 ]
+                                parser.getTokens( 6, false, "\n\r\t ,;[]" );
+                                std::array<float, 6> soundproofing;
+                                parser
+                                    >> soundproofing[ 0 ]
+                                    >> soundproofing[ 1 ]
+                                    >> soundproofing[ 2 ]
+                                    >> soundproofing[ 3 ]
+                                    >> soundproofing[ 4 ]
+                                    >> soundproofing[ 5 ];
+                                m_pasystem.soundproofing = soundproofing;
+                                continue;
+                            }
+
                             auto const lookup { announcements.find( token ) };
                             auto const announcementtype { (
                                 lookup != announcements.end() ?
                                     lookup->second :
                                     announcement_t::idle ) };
                             // NOTE: we retrieve key value for all keys, not just recognized ones
-                            auto announcementsound{ deserialize_random_set( parser ) };
-                            replace_slashes( announcementsound );
                             if( announcementtype == announcement_t::idle ) {
+                                token = parser.getToken<std::string>();
                                 continue;
                             }
+/*
+                            auto announcementsound { deserialize_random_set( parser ) };
+                            replace_slashes( announcementsound );
+*/
                             sound_source soundtemplate { sound_placement::engine }; // NOTE: sound range gets filled by pa system
-                            soundtemplate.deserialize( announcementsound, sound_type::single );
+                            soundtemplate.deserialize( parser, sound_type::single );
                             soundtemplate.owner( this );
                             m_pasystem.announcements[ static_cast<int>( announcementtype ) ] = soundtemplate;
                         }
                     }
+                    // set provided custom soundproofing to assigned sounds (for sounds without their own custom soundproofing)
+                    if( m_pasystem.soundproofing ) {
+                        for( auto &announcement : m_pasystem.announcements ) {
+                            if( !announcement.soundproofing() ) {
+                                announcement.soundproofing() = m_pasystem.soundproofing;
+                            }
+                        }
+                    }
                 }
 
 			} while( ( token != "" )
diff --git a/DynObj.h b/DynObj.h
index cf614561..aa60fb21 100644
--- a/DynObj.h
+++ b/DynObj.h
@@ -417,6 +417,7 @@ private:
     // single source per vehicle
     struct pasystem_sounds {
         std::array<sound_source, static_cast<int>( announcement_t::end )> announcements;
+        std::optional< std::array<float, 6> > soundproofing; 
         sound_source announcement;
         std::deque<sound_source> announcement_queue; // fifo queue
     };
diff --git a/driverhints.cpp b/driverhints.cpp
index 90c5f92f..fb0af11d 100644
--- a/driverhints.cpp
+++ b/driverhints.cpp
@@ -938,7 +938,7 @@ TController::cue_action( locale::string const Action, float const Actionparamete
             hint(
                 Action,
                 [this](float const Parameter) -> bool {
-                    return ( ( mvControlling->Sand == 0 ) || ( mvControlling->SandDose == true ) ); } );
+                    return ( ( mvControlling->Sand == 0 ) || ( mvControlling->SandDose == true ) || ( mvControlling->SlippingWheels == false ) ); } );
             break;
         }
         case locale::string::driver_hint_sandingoff: {
diff --git a/version.h b/version.h
index c7002bc9..db807e11 100644
--- a/version.h
+++ b/version.h
@@ -1,5 +1,5 @@
 #pragma once
 
 #define VERSION_MAJOR 21
-#define VERSION_MINOR 424
+#define VERSION_MINOR 426
 #define VERSION_REVISION 0