diff --git a/DCCWaveform.cpp b/DCCWaveform.cpp
index f66da28..dc4b503 100644
--- a/DCCWaveform.cpp
+++ b/DCCWaveform.cpp
@@ -123,10 +123,13 @@ void DCCWaveform::setPowerMode(POWERMODE mode) {
 
 void DCCWaveform::checkPowerOverload() {
   
+  static int progTripValue = motorDriver->mA2raw(TRIP_CURRENT_PROG); // need only calculate once, hence static
+
   if (millis() - lastSampleTaken  < sampleDelay) return;
   lastSampleTaken = millis();
   int tripValue= motorDriver->rawCurrentTripValue;
-  if (!isMainTrack && (ackPending || progTrackSyncMain))   tripValue=ACK_CURRENT_TRIP;
+  if (!isMainTrack && !ackPending && !progTrackSyncMain)
+    tripValue=progTripValue;
   
   switch (powerMode) {
     case POWERMODE::OFF:
@@ -143,8 +146,8 @@ void DCCWaveform::checkPowerOverload() {
 	  if (power_sample_overload_wait>POWER_SAMPLE_OVERLOAD_WAIT) power_sample_overload_wait=POWER_SAMPLE_OVERLOAD_WAIT;
       } else {
         setPowerMode(POWERMODE::OVERLOAD);
-        unsigned int mA=motorDriver->convertToMilliamps(lastCurrent);
-        unsigned int maxmA=motorDriver->convertToMilliamps(tripValue);
+        unsigned int mA=motorDriver->raw2mA(lastCurrent);
+        unsigned int maxmA=motorDriver->raw2mA(tripValue);
         DIAG(F("\n*** %S TRACK POWER OVERLOAD current=%d max=%d  offtime=%l ***\n"), isMainTrack ? F("MAIN") : F("PROG"), mA, maxmA, power_sample_overload_wait);
 	power_good_counter=0;
         sampleDelay = power_sample_overload_wait;
@@ -287,7 +290,7 @@ int DCCWaveform::getLastCurrent() {
 void DCCWaveform::setAckBaseline() {
       if (isMainTrack) return; 
       ackThreshold=motorDriver->getCurrentRaw() + (int)(65 / motorDriver->senseFactor);
-      if (Diag::ACK) DIAG(F("\nACK-BASELINE %d/%dmA"),ackThreshold,motorDriver->convertToMilliamps(ackThreshold));
+      if (Diag::ACK) DIAG(F("\nACK-BASELINE %d/%dmA"),ackThreshold,motorDriver->raw2mA(ackThreshold));
 }
 
 void DCCWaveform::setAckPending() {
@@ -303,7 +306,7 @@ void DCCWaveform::setAckPending() {
 byte DCCWaveform::getAck() {
       if (ackPending) return (2);  // still waiting
       if (Diag::ACK) DIAG(F("\nACK-%S after %dmS max=%d/%dmA pulse=%duS"),ackDetected?F("OK"):F("FAIL"), ackCheckDuration, 
-           ackMaxCurrent,motorDriver->convertToMilliamps(ackMaxCurrent), ackPulseDuration);
+           ackMaxCurrent,motorDriver->raw2mA(ackMaxCurrent), ackPulseDuration);
       if (ackDetected) return (1); // Yes we had an ack
       return(0);  // pending set off but not detected means no ACK.   
 }
diff --git a/DCCWaveform.h b/DCCWaveform.h
index b1c6f7d..5af7144 100644
--- a/DCCWaveform.h
+++ b/DCCWaveform.h
@@ -105,7 +105,9 @@ class DCCWaveform {
     POWERMODE powerMode;
     unsigned long lastSampleTaken;
     unsigned int sampleDelay;
-    static const int ACK_CURRENT_TRIP=1000; // During ACK processing limit can be higher
+    // Trip current for programming track, 250mA. Change only if you really
+    // need to be non-NMRA-compliant because of decoders that are not either.
+    static const int TRIP_CURRENT_PROG=250;
     unsigned long power_sample_overload_wait = POWER_SAMPLE_OVERLOAD_WAIT;
     unsigned int power_good_counter = 0;
 
diff --git a/MotorDriver.cpp b/MotorDriver.cpp
index 75b5d05..5420488 100644
--- a/MotorDriver.cpp
+++ b/MotorDriver.cpp
@@ -76,6 +76,9 @@ int MotorDriver::getCurrentRaw() {
   return analogReadFast(currentPin);
 }
 
-unsigned int MotorDriver::convertToMilliamps( int raw) {
+unsigned int MotorDriver::raw2mA( int raw) {
   return (unsigned int)(raw * senseFactor);
 }
+int MotorDriver::mA2raw( unsigned int mA) {
+  return (int)(mA / senseFactor);
+}
diff --git a/MotorDriver.h b/MotorDriver.h
index 8dbee0a..cce07ad 100644
--- a/MotorDriver.h
+++ b/MotorDriver.h
@@ -27,7 +27,8 @@ class MotorDriver {
     virtual void setSignal( bool high);
     virtual void setBrake( bool on);
     virtual int  getCurrentRaw();
-    virtual unsigned int  convertToMilliamps( int rawValue);
+    virtual unsigned int raw2mA( int raw);
+    virtual int mA2raw( unsigned int mA);
   
     byte powerPin, signalPin, signalPin2, brakePin,currentPin,faultPin;
    float senseFactor;
diff --git a/MotorDrivers.h b/MotorDrivers.h
index b7ed3de..3695e0a 100644
--- a/MotorDrivers.h
+++ b/MotorDrivers.h
@@ -10,40 +10,37 @@
 // This file contains configurations for known/supported motor shields.
 // A configuration defined by macro here can be used in your sketch.
 // A custom hardware setup will require your sketch to create MotorDriver instances
-// similar to those defined here, WITHOUT editing this file.
+// similar to those defined here, WITHOUT editing this file. You can put your
+// custom defines in config.h.
 
 const byte UNUSED_PIN = 255;
 
-// Trip current for programming track in mA. Change only if you really
-// need to be non-NMRA-compliant because of decoders that are not either.
-#define TRIP_CURRENT_PROG 250
-
 // MotorDriver(byte power_pin, byte signal_pin, byte signal_pin2, byte brake_pin, byte current_pin,
 //             float senseFactor, unsigned int tripMilliamps, byte faultPin);
 
 // Arduino standard Motor Shield
 #define STANDARD_MOTOR_SHIELD F("STANDARD_MOTOR_SHIELD"),                                                 \
                               new MotorDriver(3, 12, UNUSED_PIN, UNUSED_PIN, A0, 2.99, 2000, UNUSED_PIN), \
-                              new MotorDriver(11, 13, UNUSED_PIN, UNUSED_PIN, A1, 2.99, TRIP_CURRENT_PROG, UNUSED_PIN)
+                              new MotorDriver(11, 13, UNUSED_PIN, UNUSED_PIN, A1, 2.99, 2000, UNUSED_PIN)
 
 // Pololu Motor Shield
 #define POLOLU_MOTOR_SHIELD F("POLOLU_MOTOR_SHIELD"),                               \
-                            new MotorDriver(4, 7, UNUSED_PIN, 9, A0, 18, 2000, 12), \
-                            new MotorDriver(2, 8, UNUSED_PIN, 10, A1, 18, TRIP_CURRENT_PROG, UNUSED_PIN)
+                            new MotorDriver(4, 7, UNUSED_PIN, 9, A0, 18, 3000, 12), \
+                            new MotorDriver(2, 8, UNUSED_PIN, 10, A1, 18, 3000, UNUSED_PIN)
 
 // Firebox Mk1
 #define FIREBOX_MK1 F("FIREBOX_MK1"),                                                  \
                     new MotorDriver(3, 6, 7, UNUSED_PIN, A5, 9.766, 5500, UNUSED_PIN), \
-                    new MotorDriver(4, 8, 9, UNUSED_PIN, A1, 5.00, TRIP_CURRENT_PROG, UNUSED_PIN)
+                    new MotorDriver(4, 8, 9, UNUSED_PIN, A1, 5.00, 1000, UNUSED_PIN)
 
 // Firebox Mk1S
 #define FIREBOX_MK1S F("FIREBOX_MK1A"),                                            \
                      new MotorDriver(24, 21, 22, 25, 23, 9.766, 5500, UNUSED_PIN), \
-                     new MotorDriver(30, 27, 28, 31, 29, 5.00, TRIP_CURRENT_PROG, UNUSED_PIN)
+                     new MotorDriver(30, 27, 28, 31, 29, 5.00, 1000, UNUSED_PIN)
 
 // FunduMoto Motor Shield
 #define FUNDUMOTO_SHIELD F("FUNDUMOTO_SHIELD"),                                              \
                          new MotorDriver(10, 12, UNUSED_PIN, 9, A0, 2.99, 2000, UNUSED_PIN), \
-                         new MotorDriver(11, 13, UNUSED_PIN, UNUSED_PIN, A1, 2.99, TRIP_CURRENT_PROG, UNUSED_PIN)
+                         new MotorDriver(11, 13, UNUSED_PIN, UNUSED_PIN, A1, 2.99, 2000, UNUSED_PIN)
 
 #endif