@Steve "Papa" Eastman finally found the book I was looking for, sorry for the delay. According to Carsten's Publications C6 "Toy Trains of Yesteryear"(I'm sure that 99% of you have seen it and a high percentage have read it, as well) Your Bing 3238, quoting the source, "There were two popular Bing electric types that headed the list of American best sellers; a short stubby type and a long body slender type. The bodies of each of these 0-4-0 engines were made of fine detailed foundry cast iron....similar to the Ives bodies. Unlike Ives, Bing made separate cast iron pilots which were attached to the underframe casting by two machine screws...."(if a pilot broke, replacing it would)...prove no problem....(as opposed to Ives in which case)... the entire underbody had to be replaced."(Toy Trains of Yesteryear, Carstens Publications, Copyright 1972).
Also, I was mistaken, my 4 wheel baggage car is also #501. At the top end, it has "The Bing Miniature Railroad System"(logo b3 in the picture I posted). I acquired that piece with a few other Bing 4 wheel cars, none of which had "Kenosha" on them. However, I purchased those cars as random lot being sold. That said, post-WWI, 1920s would be my best guess!
Hope that provided some help. Once again, I am sorry for the delay!
