I have found some little infomation about Season 12 of Thomas & Friends on a news website but I've forgotton the website.

Title Unknown: Thomas and Percy meet Hank the Big American Engine.

Title Unknown: Thomas has an accident with his trucks when racing Harold so it's up to him to help Thomas.

Title Unknown: Toby is jealous of Flora when she takes Henrietta.

I'm looking foward to finding out more infomation.