Translation:Trains are big.
I'm pretty sure word order is of the matter here. "It's a big train" would be 大きい電書です
Please correct me if I'm wrong, I only recently started learning
yes what is the difference between. trains are big and. it is a big train. furethermore. how can we know it is plural for train?
A train is big: 電車は大きいです。 Trains are big: 電車は大きいです。
It is a big train: 大きい電車です。 They are big trains: 大きい電車です。
Japanese doesn't distinguish between singular and plural, so you'd only know through context.
If the answer is "trains" in plural, and not a single "train", why wouldn't there be "tachi" after the sign for train?
たち is not a true plural, it only ever means "--and their associates". For example, 私たち can be translated as "we/us", but it most accurately transliterates as "me and my associates". This is why you can only use it for people; you can't attach it to inanimate objects like trains and expect it to work.
でんしゃ, or "densha" in romanji.
someone once partially confused it with 自転車/じてんしゃ/jitensha (bicycle) on account of the で and て looking very similar