Photo Credit: Alex Mead
Seen above is a pair of machines that use one of the most widespread civil engineering systems in the world: the railroad network. These machines are known as locomotives and run on diesel fuel to transport everything from coal, to livestock, to people on the thousands of miles of track that comprise the rail network. Locomotives today are mainly diesel-electric in nature. That is, they burn diesel fuel in an internal combustion engine which turns a generator to make electricity. This electricity is then used to power motors connected to the wheels. This power system is advantageous because no transmission, a complicated mechanical component, is needed to transfer the power from the diesel engine to the wheels.