Yes - I need one.
The technical bit - both locos actually have Bissel trucks but on the Harz these are connected to the driven axles - hence the
Schwartzkopff-Eckhardt-Lenkgestell, being a method of moving the main driven axles sideways to assist cornering - an improvement to the
Golsdorf system of articulation. I assumed the Saxon locos also have these but I will now have to go and find out.
Well - I have to turn on my pedantic mode (sorry - I cannot resist) - the whole story is a bit more complex.
VII k (750 mm) has only Bissel trucks which can swing +/- 120 mm (pivot point fixed at the frame) , the 1st and 4th driving wheels are fixed, the 2nd and 5th driving wheels can move +/- 6mm sidewards,
the main driving wheel has reduced flanges to handle 50 meters radii.
The 99. 72 (Harz 1.000 mm) had never Bissel trucks, but initially Krauss-Helmholtz-bogies between pony truck and 1st driving wheel.

source:
Krauss-Helmholtz-Lenkgestell – Wikipedia
Here some pics from our 65 1057 - the principle is the same on class 50 / 52 etc.
In front the pony truck, in the middle the big lever, and in the background the 1st driving wheel . The pivot point is not fixed but equipped with damper-Springs so that not every movement / bump will directly be transferred to the loco-frame.
This Krauss-Helmoltz priciple failed in sharp curves, so all Harz-locos received the Schwartzkopff-Eckardt-bogies.
It's a combination of Krauss-Helmholtz between pony and 2nd driving wheel (blue lever) plus a Beugniot-lever between 1st and 2nd driving wheel (orange lever).

source:
Schwartzkopff-Eckhardt-Lenkgestell – Wikipedia
In combination with a flangeless driving axle the Harz-2-10-2 locos have no fixed wheelbase, just a "guided length".
The same principle was applied on standard gauge class 84 on the Heidenau-Altenberg track which was re-gauged in 1935 - 1938
-pedantic mode off-.
When I made my fireman license in the early 90's in Wernigerode - I can tell you it takes quite some time to oil all theses levers and to fill all oil containers. Just don't forget one!