Yes ITC available on Official trips, but company Pay Train ticket or bus ticket to his employees for vacation, ITC is not available. please refer sec 17(5).
Yes, you can avail ITC since used in the course or furtherance of Business. Just ensure that all the FOUR CONDITIONS as laid down under Section 16(2) of the CGST Act 2017 is satisfied before claiming it in your GSTR-3B Return.