The 99s, together with the 98s, 17s, 18s, 38s etc, are a "pool class". In 1920, with the founding of the "Reichsbahn", the rolling stock incorporated from the former state railways had to be orderly designated and divided into classes. Obviously, it was not very feasible to give each class of the state railways their own Reichsbahn class number, this would have led to a vast and unnecessary number of locomotive classes. These designations were for locomotives of German part state railways locomotives with similar purposes but different designs. Since the class 17, 18, 38 were well-defined from the axle formula and purpose (hence roughly similar machine size and performance), the 99s where narrow gauge machines of all types. So the 99 class designation never defined a certain locomotive but only "not standard gauge". So you can find anything between a 2'E meter gauge 80ton gauge heavy duty mountain railway machine to a B 750mm gauge 20ton narrow gauge light service machine in the class, which is confusing in the first glance. Also, the class 98 was a standard gauge class for "the rest", containing everything from small and heavy shunters to proper branch railway haulers, goods or commuter or mixed service. Speaking 99s, also all the other pool classes (which are a similar collection of "the rest"), you'll always add the two numbers behind the main class to the designation like not "99", but "99.51" etc. instead.

The story of the Class 06 is quite a complicated one. It would have required some major reworking, but it could have been a successful locomotive if it weren't for WW2.

Cobi is making the BR 03 if you're interested

Thank you so much for your support and your kind words! It always makes me happy to hear my videos are valuable to others. Happy Holidays! PS: This pronunciation just seemed the most logical to me. But I have to admit, I wasn't entirely sure, so I appreciate the confirmation!

Thank you so much! And Frohe Weihnachten!

Doing such a comparison sounds like a good idea, but I'm not sure If I can fit it into my schedule any time soon, so no promises just yet. About the short tenders, some of them were later reused for certain routes that still required locomotives to be turned on short turntables, including other standard classes that were originally built with larger ones. From the top of my head, I don't know how many were used this way, but the remainder were probably rebuilt for other uses like a snowplough, water wagon for steam cranes etc., which was very common even for tenders of withdrawn locomotives.