grammar - How do I decide when to use plain or past verb form?

In

(1) 明日、家へ帰って、母が作ったおいしい料理を食べます。

why is it 作った when it’s a future event? If I wanted to create a clause meaning 'delicious food my mother makes', it would be 母が作るおいしい料理. Does changing 作った in (1) to 作る make any sense? Or is it grammatically wrong?

EDIT: I read my own draft question wrongly and transferred it wrongly to stackexchange. I intended to ask this:

And in

(2) 私の家は郊外にあります。町までちょっと遠いですが、電車が走っていますから、便利です。

Why is it 走っています and not 走っていました? (I think I just solved this on my own. 走っていた + から implies 走っていた causes 便利, which clearly isn't the case)

Answer

The first sentence here forms an excellent question, because it highlights the issue of tense in subordinate clauses, which can be counter-intuitive coming from an English background.

明日、家へ帰って、母が作ったおいしい料理を食べます。

The English mind looks at this and thinks about the verb 作る relative to the time when this statement is made. Since we're talking about a future event, it would seem to make sense that the verbs (even in subordinate clauses) should match up and be in future tense. But the Japanese mind thinks about 作る relative to the time when the main action takes place. Since the main action is 食べる, at the point when 食べる takes place, the food will have already been made, so 作った, not 作る, is correct.

For another example, consider the following:

日本に行くときにデジカメを買います。

日本に行ったときにデジカメを買います。

These are both valid sentences, but they mean different things! The first, because 行く is non-past, means you will buy a camera before going to Japan (because at the time とき, the action 行く has not happened yet). But the second, because 行った is past, means you will buy a camera after having arrived in Japan (because at the time とき, the action 行く has happened).