I just received a dummy unit for my sons train set. The set is a union pacific from 1975. The dummy unit looks great and the horn works, but the speaker has a noticeable hum/buzz when running the set. Is there something that can be done to reduce this? The dummy unit is number 6-8573 , u36b. I have not been able to find much information on the unit. I also was wondering if it is supposed to have working lights. The only description I found for it didn't mention lights. Thanks for any help 

[ Attachment Invalid Or Does Not Exist ]