train

Q: If a person is standing and performing Salaah in a bus or train, does he have to face the qiblah in the beginning only or for the full duration of the Salaah? If the bus moves away from the qiblah what should he do?

Q: Is it permissible to read Salaah while travelling in a car/bus / train by sitting (as there is no place to stand)? Is this permissible for all Salaah including fard? If standing is a pillar of fard Salaah, upto what duration the Salaatul qasr is applicable in case of return journey within some days.