diff --git a/MotorDriver.h b/MotorDriver.h
index db229d5..6c39058 100644
--- a/MotorDriver.h
+++ b/MotorDriver.h
@@ -118,12 +118,12 @@ class MotorDriver {
     inline byte getFaultPin() {
 	return faultPin;
     }
-    inline void setResetCounterPointer(byte *bp) {  // load resetPacketCounter pointer
+    inline void setResetCounterPointer(volatile byte *bp) {  // load resetPacketCounter pointer
       resetsCounterP = bp;
     }
     void checkPowerOverload(bool useProgLimit, byte trackno);
   private:
-    byte *resetsCounterP = NULL; // points to the resetPacketCounter if this is a prog track
+    volatile byte *resetsCounterP = NULL; // points to the resetPacketCounter if this is a prog track
     void  getFastPin(const FSH* type,int pin, bool input, FASTPIN & result);
     void  getFastPin(const FSH* type,int pin, FASTPIN & result) {
 	getFastPin(type, pin, 0, result);
diff --git a/TrackManager.cpp b/TrackManager.cpp
index 0c5117b..ccbed6f 100644
--- a/TrackManager.cpp
+++ b/TrackManager.cpp
@@ -78,11 +78,11 @@ void TrackManager::Setup(const FSH * shieldname,
 }
 
 void TrackManager::addTrack(byte t, MotorDriver* driver) {
-     track[t]=driver;
      trackMode[t]=TRACK_MODE_OFF;
+     track[t]=driver;
      if (driver) {
-         lastTrack=t;
          track[t]->setPower(POWERMODE::OFF);
+         lastTrack=t;
      } 
 }
 
@@ -167,9 +167,18 @@ bool TrackManager::setTrackMode(byte trackToSet, TRACK_MODE mode, int16_t dcAddr
     // re-evaluate HighAccuracy mode
     // We can only do this is all main and prog tracks agree
     bool canDo=true;
-    FOR_EACH_TRACK(t)
-        if (trackMode[t]==TRACK_MODE_MAIN ||trackMode[t]==TRACK_MODE_PROG)
-            canDo &= track[t]->isPWMCapable();
+    FOR_EACH_TRACK(t) {
+      // DC tracks must not have the DCC PWM switched on
+      // so we globally turn it off if one of the PWM
+      // capable tracks is now DC or DCX.
+      if (trackMode[t]==TRACK_MODE_DC || trackMode[t]==TRACK_MODE_DCX) {
+	if (track[t]->isPWMCapable()) {
+	  canDo=false;
+	  break;
+	}
+      } else if (trackMode[t]==TRACK_MODE_MAIN || trackMode[t]==TRACK_MODE_PROG)
+	canDo &= track[t]->isPWMCapable();
+    }
     //DIAG(F("HAMode=%d"),canDo);
     if (!canDo) {
       DCCTimer::clearPWM();
diff --git a/TrackManager.h b/TrackManager.h
index 8b12f86..fcbda17 100644
--- a/TrackManager.h
+++ b/TrackManager.h
@@ -23,7 +23,7 @@
 #include "MotorDriver.h"
 // Virtualised Motor shield multi-track hardware Interface
 
-enum TRACK_MODE : byte {TRACK_MODE_MAIN, TRACK_MODE_PROG, TRACK_MODE_OFF,
+enum TRACK_MODE : byte {TRACK_MODE_OFF, TRACK_MODE_MAIN, TRACK_MODE_PROG,
                         TRACK_MODE_DC, TRACK_MODE_DCX};
 
 // These constants help EXRAIL macros say SET_TRACK(2,mode) OR SET_TRACK(C,mode) etc.