Three rail comment: There were early TAS, (Train America Studio), Lionel TMCC, SAW and SAW Gen2 boards. (SAW) ( Lionel licensed components for, Sunset 3rd rail, Atlas, Weaver) that had a lot of different gingerbread functions, but the board design failed, and often. TAS increased mother board design to a full 8 amps to solve the problem. O scale, two can motor, models don't appear to draw more than 2 or 3 amps, but start/stall amperage is probably a good bit more. You may be seeing the same problem with your decoders. Board dissipation of heat another concern. The second time around on design, a much larger heat sink was added to dissipate heat. At 8 amps, the motors will fry first, been there, done that. You can also melt plastic with this amount of energy. IMO, Mike CT.
Add note: There were a few Atlas O-scale two rail models equipped with Lionel TMCC boards, Dave C mentioned this. An attempt at O-scale AC two rail. 20 years ago.
There are three component boards. Drive board (R2LC), Sound board, Sound power board Modular board plugged-in to a larger mother board.
Atlas SW model with TMCC. Note the large aluminum heat sink, located to the front of the model, before the front truck tower.
