A fun area of research in recent years has been toy trains. There are collectors who have developed massive amounts of materials on dating, production, variations, history and prices for toy trains on an amazing scale. But very few of these people are interested in technical characteristics, at least in an analytic sense. So, the field is wide open to investigate these things, especially questions like, "Why was this done?" For example, about 1927 to 1928 with the Ives company in serious financial trouble, why did they expend the resources to develop a new standard gauge motor? The simple answer is that there were problems with the early motor. I have takena quantitative look at this issue. Lionel produced a locomotive No. 42 that had a variation that allowed shunt operation (for DC) of its motors. Here is a list of documents. (Most of these files are pretty big due to the figures included. Later I may be able to cut some of them down.)
