According to Whyte
notation a steam locomotive that has a two-axle leading truck,
two powered driving axles and a one-axle trailing truck is
referred to as a 4-4-2 or "Atlantic". Atlantics, while not
well-fitted for mountain runs or long distances, were perfect
for short runs at 70 -100mph due to the large diameter driving
wheels the possessed.
Built for passenger
service, many railroads employed the use of this type of steam
locomotive for express, commute and local service. One of the
most well-known fleets of 4-4-2s were those in the service of
the Pennsylvania Railroad, who had many in operation on their
rail lines.
