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EU20-25, location unknown. My data give ‘March 1959’, but the
locomotive still bears the old designation E05-25. Photo from my collection.
EU20-17,
date and location unknown. Source: as above.
EU20-24 at the Railway Museum in Warsaw. Photo taken on September 5, 2006.
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In early 1950s PKP had only eighteen electric
locomotives suitable for regular line traffic: two EP01s (pre-war machines of
British origin), eight EP02s (modernized variant of the former, assembled in Poland
by Pafawag) and eight EP03s (built in Sweden
by ASEA in 1951 and 1952). Based on
technologies dating from the 1930s, they had little potential for further
development, if any. Polish locomotive industry was not yet ready to
undertake design and manufacture of electric locomotives; indigenous ET21,
based to a certain extent on Soviet VL22M, appeared in the
prototype form only in 1957. It had been decided, however, that
electrification would be proceeded with, and supplies from Eastern Block
countries were initially considered the only acceptable solution.
In early 1950s negotiations were
started with VEB
Lokomotivbau-Elektrotechnische Werke ‘Hans Beimler’ of Hennigsdorf, Eastern Germany (known as LEW and located at former Borsig plant, now a division of ADTranz). Orders were finally placed
in 1953 and included, apart from thirty-seven EMUs (35 class EN56 for
suburban traffic and two class ED70 for long-distance traffic), also
universal electric locomotives: 25 four-axle and 34 six-axle ones. The
former, initially classed E04 and after 1958 re-classed EU04, were used
mainly with passenger trains (this class is described under a separate
entry). The latter were intended principally for heavy freight traffic.
Delivered between 1955 and 1958, they were classed E05 and later re-classed
EU20.
EU20 was, of course, much heavier
than EU04, but due to the Co’Co’ layout axle load was in fact slightly
reduced. These two locomotives had the same traction engines and many other
sub-assemblies, including e.g. air compressors and current converters. At the
time of their introduction, EU04 and EU20 were the most modern electric
locomotive types in PKP service.
Both were basically considered universal machines, but EU20s were assigned
mainly to heavy freight traffic between Warsaw and Upper Silesia (electrified in
1957) and only sporadically hauled passenger trains. At almost the same
overall weight as early production ET21s, their continuous rating was higher
by over 20%. Despite design maximum speed of 110 km/h, their running
qualities at higher speeds left much to be desired. Initially they were based
at the Piotrków Trybunalski depot and stayed there for most of their service
life.
Just as with EU04s, there were
problems with poor reliability. In particular, failures of cast-iron startup resistors
were commonplace, due to inadequate cooling. Availability rates were
comparatively low, at least initially, and withdrawals started quite early;
first EU20 was written off in 1976 and the last one followed five years
later. EU20-24 (LEW 7817/1957) has been preserved at the Railway Museum in Warsaw. This
locomotive is on static display and sports an early livery variant, with two
shades of green separated by a narrow red strip running along the body and
V-shaped at front and rear walls.
Main technical data
|
No.
|
Parameter
|
Unit
|
Value
|
|
1.
|
Years
of manufacture
|
-
|
1955 – 1958
|
|
2.
|
Total
built / used in Poland
|
-
|
34 / 34
|
|
3.
|
Axle
arrangement
|
-
|
Co’Co’
|
|
4.
|
Control
|
-
|
multiplied
|
|
5.
|
Design
maximum speed
|
km/h
|
110
|
|
6.
|
Traction
motors (number X type)
|
-
|
6 ´ GBM530
|
|
7.
|
Voltage
|
V
|
3000
|
|
8.
|
One-hour
rating
|
kW/hp
|
3180 / 4325
|
|
9.
|
Continuous
rating
|
kW/hp
|
2520 / 3427
|
|
10.
|
Electric
current at one-hour rating
|
A
|
378
|
|
11.
|
Electric
current at continuous rating
|
A
|
295
|
|
12.
|
Rotational
speed at one-hour rating
|
rpm
|
745
|
|
13.
|
Rotational
speed at continuous rating
|
rpm
|
820
|
|
14.
|
Engine
suspension
|
-
|
nose-suspended
|
|
15.
|
Reduction
gear ratio
|
-
|
81:21
|
|
16.
|
Diameter
of drivers
|
mm
|
1350
|
|
17.
|
Total
weight
|
kg
|
120 000
|
|
18.
|
Axle
load
|
T
|
20.0
|
|
19.
|
Axle
base
|
mm
|
13 400
|
|
20.
|
Overall
length
|
mm
|
18 500
|
|
21.
|
Maximum
width
|
mm
|
3 050
|
|
22.
|
Brake
type
|
-
|
Knorr two-stage
|
References and acknowledgments
Concise
description can be found in AL.
|