Since the inability to run Menards engines in conventional mode is considered to be a show stopper by some folks (including myself), I'm sharing this video that I stumbled upon. It deals with how to control the speed of Menards and Lion Chief engines using a conventional transformer.
I'm posting it for a couple of reasons. First, it may help someone who wants to use a transformer to control speed, and second, some of the forum's electronics gurus might point out potential problems or concerns with the approach.
IMO, the approach is not very useful, as it still requires the use of the proprietary remote to run the locomotive, change direction, and initiate the horn/bell, which defeats the purpose of running in conventional mode. (To me, the need for a remote that can be broken or lost and is not available as a separate-sale item is especially problematic for Menards engines.) Also, the video goes a bit over the top by showing how to run a conventional and Menards engine together - not sure why anyone would want to do that, but in any case, it's in there.