As a change from ballasting and installing cable troughs, I went and raided some plastic kits to make this:

Not that exciting in concept, but exciting for me because I

1) Saw it in a prototype photo

2) Guessed what it might be

3) Confirmed my guess (thanks helpful RMWebbers!) and got some more information

4) Figured out some rough dimensions

5) ...

6) Made it!

As someone who's relatively clueless about the real railway this was obviously quite satisfying. The system works!

The component parts are two plastic N gauge wheels from a Green Max kit I've had for ages, face to face, for the inner barrel. These are capped with roadwheel hubs from a 1/35 Trumpeter Flakpanzer I bought cheap since I wanted the drivetrain parts for another project. Pleasingly it has with different caps on different faces to reflect the profile of the real lubricators. None of this is exactly right (there should be ribs around the inner part of the drum 'bobbin', a conical fitting for the grease pipe, and more of a shoulder on the drum faces) but it's close enough and picks up some nice-but-a-bit-overscale features like the securing bolts.

Next step is to clean it up a bit, paint it yellow and figure out how to make and fit the pump, piping, and a representation of the grease blades.