Class 520A
2-Cylinder
Fireless Shunting Locomotive
Designed by Mikhail
Rodnivacek
Built
in 1958 by
RSR Works, Bevice-Akohniçe, Ruhnia
It was recognised
early on by many railway adminstrations
that the one area of activity in which the steam locomotive was at its
least efficient was shunting, mainly because of the need to keep steam
up between turns of duty. In most cases, this problem was met by the
introduction of diesel locomotives. A separate infrastructure for these
was unavoidable and provided an invaluable foot in the door for
wholesale conversion to diesel power. Not so on the RSR. Since most of
the RSR's marshalling yards were in close proximity to
the country's industrial areas,
a ready supply of steam was almost always to hand. The class 520A
shunters were created to take advantage of this circumstance. It was a
relatively simple matter to set up stationary boilers in other
locations.
The fireless
locomotive has only a steam reservoir. This is a simple drum and can
thus be charged at high pressure without the problems that arise
from the complex structure of a boiler. The class 523B 0-10-0Ts were
classical shunting engines with the typical disadvantages mentioned
above. All twenty locos of the class, as they passed through the shops,
lost their boilers - which were reconditioned and placed in store as
spares - and were fitted with steam drums. As is usual with a fireless
loco, the cab was placed at the former front end above the cylinders to
keep the steam pipes as short as possible. The storage drum is pressed
to fifty atmospheres, the working pressure of 17 atmospheres
being generated by means of a
reducing valve. The 523B running
gear was retained with only minor modifications - due to the low
working speeds no benefit was expected from poppet valve gear.
Exhaust is directly to the
atmosphere via the vertical pipe and silencer behind the cab. The first ten examples were
placed in service in Bevice and Forihv, the remainder being widely
scattered around the system.