These bricks will help to build a sloping track. You can build very high and very stable bridges or steep ramps. They can also be used to build angled roofes for houses when you attach plates to them.

The numbers 1,2,3 indicate the incline of the rail (unit: bricks per 1 rail) attached to this brick.
You will notice that the Duplo trains have a limited ground clearance, and that you can not start nor end a slope with a 2 or 3 bricks incline or your train will get stuck.
The trains are capable to climb this (max 27°) incline without trailers. Their motors are powerfull enough and the traction is just ok even your rails have no teeth like the genuine DUPLO bridges. Just downhill the train can start to slide with the °3 bricks, but the train won't slip off the track.

The bricks have a wall thickness of 1.2mm, and their height are multiples of 0.3mm. Therefore I recommend to print them with 0.6mm nozzle and 0.3mm layer height, no support just bridge detection. One brick has a print time of 40 minutes with these settings.