Class
423D 2-Cylinder General Purpose Locomotive
Designed
by Mikhail Rodnivacek
Built
in 1954 by Friedrich Krupp, Essen, Germany
It
was, indirectly, thanks to Frihdrik Tešlov that these fine locomotives
and their 4-8-4T cousins were built by Krupp. The contract for their
construction
was awarded just after Tešlov's 2-10-2s entered traffic and impressed
everyone. The design, of course, came from the drawing board of Mikhail
Rodnivacek, who was at this time in the process of renewing the RSR's
locomotive
stock. There was a clear need for a modern, medium-sized mixed traffic
engine for the mountain routes in the south. With their eight-coupled,
1560mm wheels, the 423Ds struck the right balance between speed and
pulling
power. The standard 2c boiler was pitched high to accommodate the wide
firebox above the driving wheels. A total of seventy 423Ds were
delivered
by Krupp during 1954 and 1955. The changeover to poppet valves on the
RSR was proceeding apace when these locomotives were delivered and came
just too late for the order to Krupp to be amended. Starting in 1956,
all engines were converted at the first opportunity (usually in
connection with the first general overhaul), becoming class 423DD.
In this form the engines remained the mainstay of medium services in the south until the mid-1980s, when the 58 survivors were rebuilt to class 434E.