Making Lady Canon in the Model Series

I saw a video talking about what makes Magic Railroad not cannon, and it got me thinking how you could make Lady canon in the model series.

I was thinking Lady could be a Culdee Fell engine in the model series. Other than Splatter, she’s the only purple engine we see. The dream sequence also mentions she works high in the mountains, but she clearly doesn’t work with the Skarloey engines. Thomas could’ve paired her up with Rusty in his dream because they both work in the mountains. The mind is weird, so it’s not crazy to think this could’ve happened. I was thinking Thomas heard of a purple mountain engine named Lady, but never actually saw her. This would explain her mystical appearance because Thomas would have to use his imagination.

My only knowledge of the Culdee Fell Railway comes from the book, so I might be missing a detail or two that brings down this head canon.