You are certainly correct that all the separate elements used in Protosound 2 for speed control existed before. But the patent was issued for the use of all those elements together for speed control of model trains in smph as well as integrating the speed control functions into the control of other features.
While it might seem that someone should have thought of it before, there apparently isn't any prior art for the application of such technology to speed control of model trains in smph.
Ted, that may be the case, but it is not sufficient that an invention be novel over the prior art to be patentable; it must be non-obvious as well.
This is why the Supreme Court's KSR decision is important. The Court held that the prior standards of non-obviousness applied by the courts and PTO were too lenient. In particular, straightforward application of technology from one field (such as automobile or robotic speed control) to another field (such as model train speed control) is likely to be obvious.
