How should we say our salat in trains and cars? Is it necessary to do prostration (sajda) on something or is it not necessary, in that would bending of the neck be sufficient?
Answer
It is obligatory to say salat in the usual way where possible. So, one should face the qiblah in all stages of the salat; if not, at least while saying the opening takbir. Otherwise the condition of facing the qiblah will be dropped. Similarly, if it is possible to do the bowing (ruku') and prostration (sajdah) normally (e.g., in the aisle of the bus or the train), those parts of salat should be done normally. But if it is not possible, then one should try to bow normally for ruku' and sajdah [for example, from a sitting position on the seat or the berth of the train].
For sajdah, one has to put the forehead on an item on which sajdah is valid, even if by lifting that item to the forehead. If bowing normally is not possible, one should just indicate by bending the neck [halfway for ruku and fully for sajdah].