Czech State Rwy 2-8-2 Locomotives in Czechoslovakia

Class 423.001 (Locobase 1652)

Data from [], last accessed 11 October 2013. See also A[nthony] E[dward] Durrant, The steam loc.

Tank locomotives were definitely needed by the new Czech State Railways after the break up of the Austro-Hungarian Empire following World War One. But a decision on superheating the boiler waffled a bit. Twenty of the first thirty locomotives were delivered with the boiler shown in these specifications.

The 010 was put up against the 011 (the first of the superheated engines) in trials that convincingly showed the superiority of the 011's hotter, drier steam. The 001s were modified to the same boiler layout as the 011.

Class 423.011 (Locobase 1654)

Data from [], last accessed 11 October 2013. See also [] . The extensive history of this class at the webzdarma website indicates that the first group with this layout were the superheater trial horses for a standard branch-line Mikado tank design. (See Locobase 1652 for the saturated engines). In tests pulling 17 empty rail cars (a trailing load of 260 tons), the superheated version reduced coal and water consumption by 20%. On a 9.2 km (5.7 mile) climb up a 2.3% grade, the 011 achieved similar savings. (Given that these results were in line with well-publicized comparisons dating back almost two decades, Locobase wonders why the tests were necessary.)

The twenty saturated 423s were converted to the same boiler layout soon thereafter.

Class 423.031 (Locobase 1653)

Data from [], a part of the Czech-language website featuring CSD steam locomotives, last accessed 11 October 2013. See also []

This was the definitive version of the superheated branch-line Mikado passenger and freight tank that was supplied to the Czech State Railways over a decade and a half beginning in 1922. Most had the Vorf_ek-Ftepán dome installation in which both the steam and sand domes were combined in one long casing that diminished the apparent size of the rest of the locomotive. Both trucks were of the familiar Adams design. The first three axles were spaced 1.35 metres (4 feet 3 1/2 inches) apart; the fourth was set 1.5 metres (4 feet 11 inches) behind the third.

The website presented by the operators of the 423.145 offer a succinct summary of the virtues of this long-lasting design.

The engines are credited with good running characteristics, versatility in satisfying traffic demands, easy on maintenance, and as 145 shows, amenable to updates. Prewar engines had more steam space in the boilers and thus handled rapid changes in grades more readily. These robust machines were nicknamed Velky Bycek (Big Bull). The 145 received the Giesel ejector stack system in the mid-1950s, an update that improved drafting. (The 145 ran until 1978 and was saved from scrapping for museum display.)

The superheater installation in all prewar 423s is described in Czech as malotrubnaty, as distinct from velkotrubnaty. Working from a zero comprehension of Czech, a good deal of Google translator help (but not those two terms), and a stray reference or two, Locobase concludes that the distinction is between smaller (malo) versus larger (velko)-diameter flues for the superheater elements. It may be that "malo" is akin to a Type E superheater, and "velko" to a Type A.

Indicated horsepower 552 kW (734 hp) and train loadings included 1,000 tonnes on the level at 50 km/h (31 mph), run up a 0.1% grade at 40 km/h (24.8 mph) and a 2% grade at 30 km/h (18.6 mph).

Class 423.161 (Locobase 15469)

Data from [] . After World War Two ended, the Czech State Railways quickly began building up its rail system . One simple decision was to continue building a very successful prewar Mikado tank design (Locobases 1652-1654), but with some changes.

The firebox was only slightly larger and the grate area remained the same, but the boiler shrank slightly in area and underwent substantial alterations. Pressure increased by 2 bar (29 psi) and the superheater flues assumed the more typical size of a Schmidt installation and the tube and flue counts a more typical ratio.

The two auxiliary axles and their adjacent driving axles were held in Krauss-Helmholz trucks. Trofimov slide valves fed the cylinders.

Indicated horsepower rose to 589 kW (790 hp) and train loadings included 1,500 tonnes on the level at 40 km/h (24.8 mph), 1,000 tonnes up a 0.5% grade at 18 km/h (11.2 mph), 500 tonnes up a 1% grade at 20 km/h (12.4 mph), and 150 tonnes up a 3% grade at 20 km/h.

The last sixty to be built (in 1948) were sufficiently different even from these to rate a new Class ID; see Locobase 1655.

Class 433.0 (Locobase 1655)

Data from [], last accessed 2 December 2006. See also the Iron Monument Club website [] and Henry Mrazek's VALAFSK- SPOLEC(NOST HISTORICKCH KOLEJOVCH VOZIDEL site at [] . This class was originally considered to be a continuation of the 423 class of Mikado tanks and in fact shared many of the dimensions of the last 71 to be built (Locobase 15469). But

The two auxiliary axles and their adjacent driving axles were held in Krauss-Helmholz trucks. Also, the four driving axles were now equally spaced, the center of each 1.4 metres (4 feet 8 inches) from the next.

Dr.. Zbynek Zlinsk', writing in Vlaky.net at [], last accessed 11 October 2013, notes that the smaller steam space in the top of the boiler caused water to be let into the cylinders--decidedly undesirable. Although the crews on services that featured frequent changes in grade were said to prefer the older series for that reason, it's also true that the entire 433 stud ran until the 1970s and 1980s.

Indicated horsepower rose to 589 kW (790 hp) and train loadings included 1,500 tonnes on the level at 40 km/h (24.8 mph), 1,000 tonnes up a 0.5% grade at 18 km/h (11.2 mph), 500 tonnes up a 1% grade at 20 km/h (12.4 mph), and 150 tonnes up a 3% grade at 20 km/h.