だったこともあり

[MeitanteiJesus]

In the following line:

ガラガラの電車だったこともあり旅の疲れもなく、せいぜい出発が早朝だったせいで眠気がある程度だ。
There was no fatigue from the trip on the rattling train, at most there was a drowsiness from departing early.

Does だったこともあり here mean "There was also" a rattling train? Is it rattling or empty? Not sure if I translated that right either.

[NileCat]

ガラガラ is a mimetic word means empty. In this case, ガラガラの is used as an adjective.
“Part of the reasons I didn't get tired is that the train was empty ～”
Well, this translation sounds awful... But I think you can at least get the meaning.

[MeitanteiJesus]

Ah I see, so だったこともあり is kind of like とか?

[NileCat]

No it isn’t.
In this case, ～あり works as ～あったので which indicates the causality.

garagara-no / densha / datta / koto / mo /ari
empty / train / that was / fact (cause) / also / being

I guess that’s similar to this sentence structure.
“Having had something, I did something.”

[MeitanteiJesus]

Thanks for clearing it all up for me.