Starting Sunday, passengers can only purchase train tickets to Beijing as early as three days ahead of their departure, the Beijing Times reported.

The decision was announced Saturday by Beijing's railway authorities. The pre-sale period is two days shorter than the previous five days.

The report quoted a railway official as reporting the move was to ensure sufficient supply of passenger train tickets in the run up to and during the August Olympics.

Students will not be affected by the adjustment and can purchase the tickets 10 days in advance.

This is the second time in a month that the pre-sale period for train tickets to the capital has been adjusted. The period was shortened to five days on July 20 from the previous ten days, following a circular issued by the Railway Ministry.