Miscellaneous Odd Boilers
KESSLER'S DOUBLE-BASS BOILER
In 1851 the 1A1 passenger train locomotive Koenig Ludwig (King Ludwig) was supplied to the German Palatinate region. This was built by Kessler with a patented Bassgeigenkessel. (Double-bass boiler) As the name elegantly suggests, this had a pear-shaped cross section; the lower part could have a reduced width compared with a conventional cylindrical boiler and could therefore be set lower down between the wheels, lowering the centre of gravity. This was a great concern at the time as a low C of G was thought essential for stability. (The actual situation is a bit more complex than that)
No illustration of the Kessler boiler has so far been found, but it is a pretty safe bet that it looked something like the French Thuile Locomotive which had a more-or-less pear-shaped boiler, to clear the driving wheels.
It is, I assume, merely a coincidence that the German word for boiler is "kessel", confusingly close to the name Kessler.The Palatine railway was absorbed by the Bavarian State Railway in 1909.
Six locomotives called "B IVs" were also built by Kessler for the Royal Bavarian State Railways (Königlich Bayerische Staatsbahn) with Kessler boilers. The success or otherwise of this plan is currently unknown, but it is significant that boilers with a non-circular cross-section have always been very rare.
THE HARTMANN BOILER
A similar result was aimed for on locomotives supplied to Bavaria by Hartmann by using two boilers: a lower boiler with a small diameter and a larger, upper boiler. This does not appear to have been satisfactory. After two boiler explosions occurred, all the engines were rebuilt with conventional boilers.
No illustration of the Hartmann boiler has so far been found.
Above: The Tender Locomotive No 254 B2 Romont: Built 1862
This "Tender Locomotive" (which means tank engine in European usage) at first sight appears to have a peculiar and interesting form of boiler. In fact it is just a saddle-tank locomotive taken to its logical conclusion, with a huge water tank completely covering the conventional boiler. Another point of interest is that it was built in 1862 by the Emil Kessler Machines-Fabrique at Esslingen, the company who experimented with the double-bass boilers described above. It was built for for the Lausanne-Fribourg-Bern railway. (Betribsnr. 4) The build-number was 578. It was taken out of use and scrapped in 1905.
Above: Another wintry view of Romont