My son is 4.5 and has been obsessed with trains since he was almost 2. This little thing is impressive. It can sense when it's about to run into an object and change its direction. The lights flash and it plays music and blow bubbles. The bubbles that it came lasted a super long time too. I think we had it on for about 15+ minutes and it was still making bubbles.
I'll try to update my review once I try store bought bubble solution, and as time goes on. The only downside to this thing is that you can't adjust the volume to the music. The music is tolerable, it's not too obnoxious in my opinion.
Update: 4/14/2019 I haven't been able to find a bubble solution that works as good as the one that comes with the toy. I have mostly tried the cheap $1 solutions from the grocery store and homemade solution, so I'll keep trying.