The final report is in: 
First, the (ERR) Electric Railroad SoundBoard, is completely outstanding. Once installed correctly, in this case a WIlliams, 2004 model, SD-40. To obtain the best performance from the soundboard in a Williams , the motors must be slowed down in order to provide 10 Volts AC to activate the horn, bell and all the steps of the motive power sounds. And at the same time not have the engine run @ top speed as it will do at 10 Volts AC.
I did plenty of research before attempting to re-wire the motors in series as required to decrease engine speed . This particular engine is an excellent runner and puller. So I didn't want to mess it up. I did have a little trouble getting the soundboard to work initially . But I switched around the power ports on the reverse board. That solved the problem.
However, I could only get full motive sound, horn, bell, in neutral . [Reason] when running, it requires the 10VAC.
I must thank Royboy, for his method and instructions on re-wiring the motors in series. I also thank Paul, [Fastfreigh], for explaining his method as well.
This WIlliams engine now operates as well if not better than any MTH Premier , Lionel Legacy , and GGM engine. The sound is absolutely perfect.
The engine speed, from a normal 1 SMPH start up to full speed @ full 18VAC approximately 60 SMPH pulling a twenty car mixed freight as smooth as silk. You learn something every day. I wish I had realized the the motors could be re-wired in series with little effort and the inexpensive engines would run like their rich cousins... This was a fun project, and this Williams engine is becoming one of my favorites. Perhaps because I have detailed, weathered, and now sound and normal speed adjustment. I don't think I'll be removing the shell again for quite some time'...
If you've been thinking of doing this adjustment to one of your orphans, I recommend you do. It is well worth it'..
I will post a short video tomorrow if all goes well timewise, of the engine in operation'...
