Thread not clear WHEN or AS with SIMPLE or CONTINUOUS

I had previously asked something like this but the thread went on and I never got an answer.

Which of these are correct?

1 I hope the train is pulling in when I arrive./when I’m arriving.

2 I hope the train pulls in when I arrive/I’m arriving.

3 The train was pulling in when my train pulled in/was pulling in.

4 The train pulled in when my train was pulling in/pulled in.

For some reason in the above sentence, the two sentences that make sense are
I hope the train pulls in when I arrive.
I hope the train is pilling in when I arrive.

But in the following example the other choices would be acceptable I think.

The train pulls in when I eat.
The train is pulling in when I'm eating.
The train pulls in when I'm eating.

These 3 sound good to me.

The following doesn't seem correct:
The train is pulling in when I eat.

Can you tell me what you think and if you can replace WHEN with AS in the bold sentences or would it be awkward.

Thank you so much