diff --git a/library/src/atb_time.cpp b/library/src/atb_time.cpp
index e643c8d..3340e4d 100644
--- a/library/src/atb_time.cpp
+++ b/library/src/atb_time.cpp
@@ -1,30 +1,40 @@
 #include "atb_time.h"
+#include <QDebugStateSaver>
 
+QDateTime const ATBTime::m_end(QDateTime::fromString("1970-01-02T00:00:00", Qt::ISODate));
 
 ATBTime::ATBTime()
-    : m_end(QDateTime::fromString("1970-01-02T00:00:00", Qt::ISODate))
-    , m_time(QDateTime::fromString("1970-01-01T00:00:00", Qt::ISODate)) {
+    : m_time(QDateTime::fromString("1970-01-01T00:00:00", Qt::ISODate)) {
 }
 
-ATBTime::ATBTime(int h, int m, int s, int ms)
-    : m_end(QDateTime::fromString("1970-01-02T00:00:00", Qt::ISODate))
-    , m_time(QDateTime::fromString("1970-01-01T00:00:00", Qt::ISODate)) {
+ATBTime::ATBTime(int h, int m, int /*s*/, int /*ms*/)
+    : m_time(QDateTime::fromString("1970-01-01T00:00:00", Qt::ISODate)) {
 
-    QTime t(h, m, s, ms);
-    m_time.setTime(t);
+    if (h == 24 && m == 0) {
+        m_time = m_end;
+    } else {
+        QTime const t(h, m, 0, 0);
+        m_time.setTime(t);
+    }
 }
 
 ATBTime::ATBTime(QString const &t)
-    : m_end(QDateTime::fromString("1970-01-02T00:00:00"))
-    , m_time(QDateTime::fromString("1970-01-01T00:00:00")) {
+    : m_time(QDateTime::fromString("1970-01-01T00:00:00")) {
 
     if (t == "24:00:00") {
         m_time = m_end;
     } else {
-        m_time.setTime(QTime::fromString(t, Qt::ISODate));
+        QTime tmp = QTime::fromString(t, Qt::ISODate);
+        if (tmp.isValid()) {
+            m_time.setTime(tmp);
+        }
     }
 }
 
+ATBTime::ATBTime(QTime const &t)
+    : m_time(QDateTime::fromString("1970-01-01T00:00:00")) {
+    m_time.setTime(t);
+}
 
 QTime ATBTime::addMSecs(int ms) const {
     return m_time.time().addMSecs(ms);
@@ -78,6 +88,9 @@ bool ATBTime::setHMS(int h, int m, int s, int ms) {
 }
 
 QString ATBTime::toString(Qt::DateFormat format) const {
+    if (m_time == m_end) {
+        return "24:00:00";
+    }
     return m_time.time().toString(format);
 }
 
@@ -86,11 +99,20 @@ bool operator!=(const ATBTime &lhs, const ATBTime &rhs) noexcept {
 }
 
 bool operator<=(const ATBTime &lhs, const ATBTime &rhs) noexcept {
+    if (rhs.m_time == rhs.m_end) {
+        return true;
+    }
     return lhs.m_time.time() <= rhs.m_time.time();
+}
 
+bool operator>=(const ATBTime &lhs, const ATBTime &rhs) noexcept {
+    return lhs.m_time.time() >= rhs.m_time.time();
 }
 
 bool operator<(const ATBTime &lhs, const ATBTime &rhs) noexcept {
+    if (rhs.m_time == rhs.m_end) {
+        return true;
+    }
     return lhs.m_time.time() < rhs.m_time.time();
 }
 
@@ -102,8 +124,22 @@ bool operator==(const ATBTime &lhs, const ATBTime &rhs) noexcept {
     return lhs.m_time.time() == rhs.m_time.time();
 }
 
-QDataStream &operator<<(QDataStream &out, ATBTime time) {
-    out << time.m_time.time();
+QDebug &operator<<(QDebug &debug, ATBTime const &time) {
+    QDebugStateSaver saver(debug);
+    if (time.m_time == time.m_end) {
+        debug.nospace() << QString("24:00:00");
+    } else {
+        debug.nospace() << time.m_time.time().toString(Qt::ISODate);
+    }
+    return debug;
+}
+
+QDataStream &operator<<(QDataStream &out, ATBTime const &time) {
+    if (time.m_time == time.m_end) {
+        out << QString("24:00:00");
+    } else {
+        out << time.m_time.time();
+    }
     return out;
 }