Confusion with へ in a sentence

Question

I'm finding this sentence a bit tricky.

光{ひかり}の川{かわ}へ願{ねが}いの橋{はし}を掛{か}け奇跡{きせき}は渡{わた}るよ

This sentence is confusing me very much! I am not sure what it means. Does it mean:

Build a bridge of wishes over the river of light and miracles will cross.

What does 掛け here mean? Does it mean to hoist a bridge ? And are the 奇跡 crossing the bridge? Sorry if my question is a bit vague!

Answer 1

What does 掛け here mean? Does it mean to hoist a bridge?

The 「掛け(る)」 here means "to build / throw (a bridge over/across a river)".
(It's usually written as 橋を[架]{か}ける.)

The へ corresponds to "over" or "across". (「川へ橋を架ける」≂「川に橋を架ける」)

And the 「願いの橋をかける」 here also has an implied, double meaning 願いをかける "make a wish".
_{(cf: 「光の川へかけた願いが、ほら、奇跡を起こすよ」) It could be Orihime and Hikoboshi's wish, but it could also be 僕たち's wish; it's about Tanabata Festival where you make a wish on stars, write it on paper strips and hang them on bamboo leaves (cf: 「その胸に仕舞い込んだ望みを、さあ書き留めて」「僕らは願う...今、奇跡は起こるよ」).}

And are the 奇跡 crossing the bridge?

Yes, I think so. I think it's metaphorically saying 奇跡 is making the lovers' wish come true on this day, by crossing the river that lies between them.

光の川へ願いの橋を掛け奇跡は渡るよ
Does it mean:
"Build a bridge of wishes over the river of light and miracles will cross."

I would probably translate it the way you do, too.

I think the line has double meanings:
「天の川に橋を架けて、奇跡が渡る」
"We build a bridge over the Milky Way, and miracles will cross the bridge / the Milky Way."
and
「星に願いをかけて、奇跡が起こる/願いが叶う」
"We make a wish on the stars, and miracles will happen / our wish will come true".

Answer 2

It is important to understand that song lyrics do not follow the same grammatical construction of regular sentences and are often nonsensical. The 'sentence' in your example is actually composed of three separate fragments (the last of which could be considered a complete sentence).

光の川へ / 願いの橋を掛け / 奇跡は渡るよ

To the shining river / build a bridge of wishes / miracles will cross (happen).

Can be rephrased into a normal sentence. Example: 光の川へ行って、願いの橋を掛けると奇跡は渡るよ。