Rules for buying rail tickets at foreign tourist quota

Hi everybody

I read In Lonely Planet(India - issued in year 2003) there is possible to buy railticket at foreign tourist quota in Mumbai CST or Central only 1 day before or even within day of departure.

When I was in New Delhi railway station in March 2004 I was able to get ticket 3 days before departure(Delhi - Jaisalmer) and even for trains which departed from quite different city(Jodhpur - Madgaon/Goa/...bought 1 week before!!). 1 week after when I wanted to buy another ticket in office in Jodhpur railway station for train from Madgaon back to Delhi they told me that I can get tickets only for train going through Jodhpur and if I want ticket Goa - Delhi I must buy it in Vasco da Gama where tourist quota is also located.

Considering informations above I would have this question:

Is it generally possible to buy for example in Mumbay Central o CST tickets Bengalore - Mysore or Bengalore - Madgaon and more than 1 day in advance or tourist quota is possible only for trains departing from Mumbai and maximally 24 hours before departure?

Thanks for information