T478.4 is a class of diesel locomotives designed, manufactured and used in the former Czechoslovakia and now used in the Czech republic (ČD Class 754) and Slovak republic (ŽSR Class 754). The locomotive is based on the T478.3 locomotive series. The most important difference was an electric train heating generator instead of the steam heating generator used on T478.3. To provide additional power needed for the heating generator, the prime mover power output was increased to 1470 kW, but the maximal power at the output of the traction generator remained the same as on Class T478.3. Another important new technology used on these locomotives was an electronic control system with an electrically controlled air brake valve and an automatic speed regulator, which was able to control not only the