Where do you get this piece?

Which set does this piece comes from (I want to get 

grey version of this plate).  

Motor Tomica Doraemon Parallel World Set (ドラえもん パラレルワールドセット) for the green track.



Motor Tomica & Plarail Basic Set (モータートミカ & プラレールベーシックセット) for the grey version.

I'd love to have several of the parallel road/rail pieces. You can also "cheat" 45-degree roads using them. (The PlaRoad system is forced into 90-degree angles)

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The gray ones can usually be found in the Japan Auctions. I had the Doraemon Parallel World Set (minus the Doraemon motorized cart) Listed on Ebay for about a year until someone bought it a couple months ago

Doraemon is one of my other favorite series, alongside Thomas and Pokémon! (If anyone ever has questions about Doraemon in particular I know more than my fair share haha.) I've been dying to find this set for ages since the idea of Doraemon's Time Machine being a car is super humorous to me (also the road/rail pieces are nice in general.

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Those sets do show up on the Japan auctions. On occasion I have seen just the Doraemon motorized cart Listed by itself.

Are all of the ones on this thread motorized?

How can you tell motorized or non with the Japanese boxed cars

If they are boxed it's simple.
Motorized have either Battery Operated Tomica B/Oトミカ (and a B- number), or Motor Tomica モータートミカ (and an A- number) in big letters on the box.

  

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If you are asking how to tell the difference between the motorized vehicles and the Tomica brand vehicles (like hot wheels/Matchbox) you can tell by looking at the wheels. There is a distinct difference in the hubs.