While spending the day setting up and playing Lego with my son, I had a go at trying to make an electric-powered train that tilts round corners. My first attempt was this:
The right-hand bogie is the motor and is at the back.
The left-hand bogie leads and swivels the vertical axle. The first two cogs transfer this turn to the horizontal. The next set of cogs reverse the direction of rotation so it tilts into the corner, and the set of three axles transfer this rotation to the two bits of Lego which form the base of the carriage. The big blue brick is a weight to keep the front bogie on the track against the resistance of the mechanism so that it transfers the turn of the corner instead of going straight on and derailing.
It kind of works. It certainly tilts rounds corners correctly, even with a heavy coach on top of the moving base. However, it doesn’t balance on straights, probably because a) it is top heavy so doesn’t naturally want to level out, and b) the first set of cogs are probably not fine enough.
It certainly needs more work, which it might possibly get over the summer. This will involve either i) moving the mechanism to the top of the carriage so the walls hang off it and so straighten automatically, or ii) making the main walls and roof free-hanging and set the mechanism up to push the body without being attached to it. I fear i will not be robust enough and won’t work anyway without some complicated counter-weight system, and ii will be jerky at the least. Perhaps some system of springs…
I should probably point out this is old-style 12V Lego railway with the third rail, about 95% of which is at least 20 years old.