K4T30 Tender BR 52 Coal Car KDL1

K4T30 Steifrahmentender

A BR 52 Tender designed by WLF in Vienna

We begin our analysis of the K4T30 Steifrahmentender with a breif history. The development of the new Kriegslokomotiven during the Second World War led to many new and hasty developments in the railway industry. Material shortage, neglect by the OKH and other entities, made planning and production difficult. Additional problems, like lack of tools and machinery as well as constant bombing by the Allies, round up the basic industry overview of the time. Further issues such as forced labor, fights between the GDL, HA, RVM and other entities, are covered in detail, in their respective sections.

Historical timeframe

During the offensive in the East in 1942, a lack of locomotives and rolling stock slowed down the advance and logistical support of the Army significantly. Shortages of fuel and various supplies meant added stress for the soldiers and civil personnel involved. A lot of the railway personnel, the so-called “Blaube Eisenbahner” or blue railroad workers, were no Wehrmacht personnel and as such, not protected by the Geneva Conventions.

The need for a new type of goods hauling locomotive was evident. It resulted in the development of the KDL1, or “Kriegsdampflokomotive 1” in 1942. The KDL1 or Baureihe 52 was a medium load locomotive, able to use poor track foundation and inferior subgrade structure. Simplification, standardization and reduction of total parts count were one of the important features, however.

Another important requirement was frost protection to service the cold temperatures in the East. The ultimate design of the BR52 was a modified and simplified version of the BR 50 from the late 30s. To use older parts, machinery and tools on top of the minimization of negative effects due to shifts in production, key components of BR 50 locomotive designs were used for the BR 50ÜK and ultimately the BR 52. One of the various types of tenders of the BR 50 was the 4T30.

K4T30 Development

Only ten or eleven BR 50s coupled the Steifrahmentender 4T30 tender. This tender had a 30m³ water capacity and 8 tons of coal. As the BR 50’s design had an open cabin, the front of the 4T30 tender had a tender front wall. Three locomotives that pulled a 4T30 are 50 2960, 50 2955, 50 3117 and 50 3054 [4,5]. There is one image of BR 50 2960 with a 4T30 tender.

The BR 52 on the other hand, featured a Norwegerhaus and their tenders needed no front wall. As a result, the K4T30 is based on the 4T30 design with fewer parts, thinner walls and simplified. Around 1250 K4T30 were manufactured, compared to some 5000 K 2’2’T 30 “Wannentender”. Characteristic advantages of the Wannentender were a major reason for their quantitative superior numbers. However, the K4T30 plaid an important role during the first months of the BR52s and BR50ÜK’s production.

A shortage of two-axle trucks led to big shortages in tenders for the BR52. However, the finished design and easy manufacturing of the K4T30 saved the BR52 program from collapse. Production of the vital locomotives would have dropped significantly, without these so-called “Steifrahmentender“. As such, the K4T30 was an important and readily available interim solution for BR 52 manufacturing.

A request for WLF to couple all their output by K4T30 led to their sole association with the Steifrahmentender tender. However, the manufacturers were actually the Rax-Werke in Austria and the Eisenwerke Kaiserslautern in Germany. Other manufacturers, like Wilhelm Hermes Stahlbau in Rosbach, manufactured them also. The factory in Rosbach vanished after the company went out of business in 1979. The planned construction of a shopping mall has not yet begun[6].

K4T30 Features

The K4T30 has 4 fixed frame axles inside the frame. It supports the tender with its 30m³ of water and 9.4m³ or 8t of coal in 1942. The empty weight of the tender is 24.5t, however, DRG documents state 23.8t as the weight and have a maximum operating weight of 60.85t. It is fairly easy to spot minor manufacturing variations when comparing official documents with those of manufacturers. See the Wilhelm Hermes Stahlbau documents and their axle load and weight numbers.

K4T30 Description Steifrahmentender
K4T30 description and manufacturing details

One of the few K4T30 still in servicw

Enjoy some images of the K4T30 of locomotive BR 52 6666 in BW Berlin Schöneweide, owned by Dampflokfreunde Berlin e.V. before we move on. Back in 2019, I had the chance to climb around and look through their locomotive sheds and take thousands of close-up images for future scale modeling references.

The rigid frame of the tender led to unfavorable conditions during reverse driving. Reversing at full speed led to higher chances of derailings and non-smooth rides. Peers like chief engineer Witte state in reports that the ride with a locomotive and the K4T30s was bumpier. Hauptausschussanweisung 39, a manufacturing demand for advanced frost protection from 1942. As a result, the placement of glass wool and other insulation material was responsible for this look. Additionally, asbestos fabric, wrapped around all pipes, helped with frost protection.

The empty tender weight per ton of fuel (water and coal) of 626.3kg is quite bad in comparison to the 467.3 of the K 2’2′ T30 tender variant. The Steifrahmentender K4T30 carried 2 tons less coal and the same amount of water. This lead to a reduced range capacity, which was often defined by the amount of coal in the bunker. The inferior carbon contents of Russian coal led to higher consumption and thus making coal the limiting range factor.


On the other hand, however, an attractive price of 25,000RM vs 88,000RM made the K4T30 attractive, from a financial perspective. Together with the aforementioned shortages of 2 axle trucks early during the war, the excessive usage of the K4T30 is obvious. Availability, lack of alternatives, low price and easy manufacturing made it lucrative. In my opinion, it is a beautiful tender and I can’t wait to have my 1/16 scale model of it finished. For further readings regarding the K4T30, make sure to read the flak on the tender article as well as the BR 52 series. For more images of the Steifrahmentender, have a look at my Flickr account here. Feel free to comment below.

Have a great start into the week and stay safe.

Sources and further readings

  1. Albert Gieseler – BR 52 – 03.05.2021
  2. Dampflokomotivarchiv – BR 52 – 03.05.2021
  3. Slezak 1971: Helmut Griebl / Hansjürgen Wenzel – Geschichte der deutschen Kriegslokomotiven
  4. EK 1988, Ebel/Wenzel, Die Baureihe 50, Band 2: Deutsche Bundesbahn
  5. Andreas B – Lokbahnhof.de – 20.04.2021
  6. Kölner Stadtanzeiger 2010 – Demolishion – 01.05.2021
  7. Historisches Rosbach
  8. Lokbaer BR52 Steifrahmentender – 03.05.2021
  9. Transpress 1998: Janus Piekalkiewicz, 5th Edition – Die Deutsche Reichsbahn im Zweiten Weltkrieg p.130
  10. Cover image: Franck 1973: Alfred B Gottwald – Deutsche Kriegslokomotiven 1939-1945 – Die Eisenbhan im Zweiten Weltkrieg Abb. 49 p55

Are there scale models available?

Yes, there are various models available in 1:35 and 1:72 scale as well as all common railroad model scales like TT, H0, N, Z, Spur 1 and many more.

Has ISA Models one under construction?

Yes we do actually have two under construction. One in 1:16 scale and in 1:35 scale. Both feature the Steifrahmentender K4T30.

Are there many K4T30s still around?

There are quite a few rusting away on various abandoned rail yards. The 52 6666 has an unmodified original Steifrahmentender up and running. Turkey also has a few, but they are heavily modified.

Were there FLAK guns mounted on them as many scale models show?

No, not at all. Check out Flak on tender for detailed research analysis. This article specifically describes it on the basis of the Steifrahmentender K4T30.

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