Sentence: He had called and I said I was working on that

[Sureshvemuri]

The context is:
I am working with a file. At that time, Person-A called me and asked about the file.
After that,after 30 Minutes, Person-B asked me what happend.
My reply was -"Person-A had called and I said I was working on that- is this correct".
Here, WAS WORKING- correct?

Whenever we tell about the past things, all presentence should be converted into Past tense? Like "is working "---> "was working".

Second thing, whenever we use "thought" - the remaining things should be changed into Past.
Ex: At 3.00 am, Person-A is on the way. Someone asked me about Person-A.
I said - "Person-A is on the way".
After 30 minutes (3.30 am), Person-B asked me about Person-A. At this point also, Person-A HAS NOT COME.
My reply (at 3.30 am)- "I thought Person-A was on the way". Is this correct - Because Person-A is STILL on his way. This actions has not finished yet.

[Mister Micawber]

.
These are correct:

First thing:　　Person　A called and I said I was working on that。

Second thing: I thought Person A was on the way
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mr. Micawber

[Sureshvemuri]

My confusion is with using "Had".

Since there are two things happened, Called + My reply - Should not I use HAD CALLED instead of "Person　A called and I said I was working on that".
This is where I confuse.
My Question: If ONE SINGLE person did do things, then only should I use Had+Past tense.

[Mister Micawber]

.
No-- use past perfect sparingly. Use it only when ( 1 ) the sequence of the two past events is unclear or ( 2 ) when you wish to or need to stress the chronology of events.
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mr. Micawber

[Daemon99]

[Mister Micawber]

.

[Daemon99]

Sorry Mister Micawber and Suresh, I forgot to mention that we could use that sentence when somebody asked us why we missed the train

And as you said, The train left when we arrived at the station is very much possible.
_________________
Non-native speaker of English
=================================
I intend to live forever - so far, so good.

[Sureshvemuri]

[Mister Micawber]

.
On the contrary, the past perfect still has its uses-- particularly in moments of ambiguity.
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mr. Micawber