Articulated Steamers

[selector]

Hi, I mostly frequent the two main Model Railroader forums. Today, someone has asked about the synchronization of the sets of valve gear and drivers on those locos, if thst is desirable or even possible. We need someone who is knowledgeable to come over and straighten us out.

Please.

[CSSHEGEWISCH]

The very nature of an articulated locomotive makes it difficult at best to synchronize valve gear and drivers. Since one set of wheels can be out of line with the other, it would take variable-length rods to do such a synchronization. According to "Articulated Locomotives" by Lionel Wiener, this has been done in the Klose design, but I'm not sure how widespread this design was.

[selector]

Thanks very much for responding. This subject got a bit of attention in the Model Railroad General Discussion pages a few days back if you'd care to have a look.

[daveklepper]

On USA Mallets and straight "simple" articulateds, there was never any attempt to synchronize the two "engines" and this was also true for the B&O and Pennsy non-articulated four cylinder locomotives. Each pair of cylinders had its own pair of valve gear. Three cylinder compounds of course do require coordination of the three cylinders, just like the two cylinders on a conventional locomotive.

The non-synchronization of the two "engines" was true of the Garrat locomotives also.

If anyone knows of locomotives that did have some sort of sycnronization of two engine beds please post!

There were four cylinder locomotives with synchronization, and these were a few experimental compound locomotives that had two high pressure and two low pressure cylinders all driving the same pairs of driving wheels like a three-cylinder compound. I don't think any were successful. Some three cylinder compounds did prove useful but maintenance costs generally had them rebuilt into two cylinder conventional locomotives.