Ikea / Brio Electric train with 2xAAA battery power and animated pistons

This model uses the commonly available 2 axle motor and gearbox  found on Ebay.   I have made it so it is powered by 2 AAA batteries and it uses a mico miniature switch for on/off.  My design has animated pistons and features large wheels with traditional spoke designs.  Grooved drive wheels allow for rubber band tyres for grip.   A hitch can be printed and glues in the desired position.  I used mini magnetic balls for the hitch.  It will pull nicely  and if a weight is added to the front in the cutout (I used a 10mm ball bearing) then it will easily climb up inclines.  I printed it using PLA+ silk filament and I would suggest using support below the axles.  Instructions for assembly are similar to my Youtube video for my 2nd model so watch that one.  Inspiration for all 3 models comes from what others have made and published but I has entirely designed these 3 models using ProDesktop 8 and Tinkercad.  

Model 1 with gears

Model 2 for instructions 

With pistons model 3