The Heywood Radial Axle… Updated

As an aside to the 1:24 Katie project, I’ve become interested in the Heywood Radiating Axle while waiting for some of the Katie research materials and references to arrive. Katie, being an 0-4-0 was not equipped with these but they were in use on 0-6-0 Ella and 0-8-0 Muriel. I’m working on a 3d CAD rendering of the Heywood system to try to fully understand its construction, and following that, after having been challenged, will attempt to machine a working axle in 1:24, probably more an exercise in madness or the early onset of dementia. At any rate, having done some research into radiating axles, I thought I’d share a few of the drawings I’ve tracked down. I don’t intend to go into the complexities of each system here. There are good references and discussions of the systems (except the Pfeiffer/Vauclain) in Mark Smithers’ Sir Arthur Heywood and the Fifteen Inch Gauge Railway.

A sleeved-axle system patented in 1870 by Englishman John Clark appears to be the first radiating axle system. The Clark system was different to Heywood’s and relied on only the axles at the extreme end of the wheelbase carrying sleeves, as did the later German Klien-Lindner system. The illustrations below are from Clark’s patent.

The drawings below show the Heywood system, which is the prototype I’m working on. Though I don’t have original patent information, it was first employed on the Heywood locomotive Ella, built in 1881.

The Klien-Lindner system was patented in 1892 and employed sleeves on the extreme end axles which could both pivot and slide with limits, and which were fitted with internal side control springs. The drawing below illustrates the complexity of this system. There is a much more complex drawing in Smithers’ book, so reduced and complex that it wouldn’t reproduce here to anyone’s advantage.

I recently discovered the following photos of Klien-Lindner axles which provide a little information. The first shows an axle in a rather worn state.

The second show reconstruction process on a Klien-Lindner at the Sandstone Heritage Trust. Unfortunately, these photos are really too small to be of much use (reproduced here full-size), but they are still of interest.

The latest system I’ve come across is the Pfeiffer/Vauclain system for Baldwin Locomotive Works patented in 1924. Once again a sleeved axle system using internal side control springs, similar in basic principal to the Klien-Lindner system.

Tags: John Clark, Klien-Lindner, Pfeiffer/Vauclain, Radiating Axle, Sir Arthur Heywood