Can I offer the prayer on the bus or train? If yes, what rules should I observe?
Prayers (as-salat) must be observed carefully, especially while on the way. Muslims must do their best to offer the prayer in its due time. If it can not be possible to stop the vehicle and you fear that you will miss the due time of the prayer, you can offer the prayer on a vehicle, too. The Almighty God decrees:
“If you fear , (offer the prayer) on foot or mounted. When you are safe, commemorate God Who taught you what you did not know, the way He has taught you.” (al-Baqarah 2:239)
In this day and age, a “mount” is not only an animal but also all types of vehicles.
Someone who fears from missing the prayer can offer the prayer on foot or on a vehicle. This can either occur on the way to home, work, school etc., or on a longer journey. If it counts a journey, the principles about the prayer of the traveler apply, as well as the principles about praying on a vehicle:
If you are on a journey, you offer the four-rakat obligatory prayers as two rakats. (Fajr and maghrib prayers are still two and three rakats.) This is not called shortening the prayer; the due number of rakats for a traveler is as such. As you can see in the fatwa below, while on a journey, dhuhr and asr prayers can be combined in the due prayer time of either of the prayers. The same rule applies to maghrib and isha prayers, too:
When it comes to heading for the direction of Masjid al-Haram (qiblah) on a vehicle, you can start the prayer by determining or estimating the direction of prayer (qibla). You can continue the prayer upon the same direction wherever the vehicle turns to. In such cases, the condition of heading for the qibla is not sought.
If you do not have the chance to bow your body (ruku) or prostrate (sajda), you can bow your head a bit down instead of bowing your body, and you can bow your head a bit lower than the first one instead of prostration on the ground.
You can pray with shoes on.
The Almighty God decrees:
“God does not bind anyone with a responsibility which is beyond their capability.” (al-Baqarah, 2:286)
 If you fear that you shall miss the due time of prayer