[Grammar] "caught" or "had caught"

[xxwzs]

Listed below are four sentences, which have bewildered me for a long time.
1. I got to the office earlier that day because I caught the 7:30 train from Paddington.
2. I got to the office earlier that day because I had caught the 7:30 train from Paddington.

3. Catching the 7:30 train from Paddington, I got to the office earlier.
4. Having caught the 7:30 train from Paddington, I got to the office earlier.
According the grammar rules taught in China, both #2 and #4 work well, especially grammatically.
So, which one(s) do you consider to be correct? And why?
Thanks to you.

 

[GoesStation]

2 and 4 work. Number 1 is wrong because it needs the past perfect used in number 2. You could use the simple past like this: I caught the 7:30 from Paddington that day so I got to the office early.

 

[tedmc]

When the adjective "earlier" is used, what is it that it is compared with?
Why not just write "early"?

 

[Tdol]

Maybe this is a difference between English variants, but #1 does not sound wrong to me.