Trains - when to buy tickets?

Hello, I will be traveling Egypt Dec. 25-31 and would love some advise on buying train tickets. I already have my sleeper train ticket which I bought online from Cairo to Aswan. However, I have not purchased any other train ticket in advance.

I will be taking the train from Aswan to Luxor. Should I be able to buy that ticket the same day I travel or even on the train?

I will then travel by train from Luxor back to Cairo and I have not decided to take either the sleeper again or an overnight 1st class train. Should either of these tickets be bought in advance before I leave for Egypt or can i buy them when I am there. How long in advance or even same day?

I'm just nervous about getting times and days I want as I have a very tight schedule.

Thanks so much for any advise!

You are fine to purchase your tickets on the train. The only exception would be if you decide to take the sleeper back from Cairo, then buy them the day before you leave.

Good luck.

Good information here:

http://www.seat61.com/Egypt.htm#.UMmmEeR1-So

Does that information apply to long-distance buses as well? I will be in Cairo in a few days and I want to go to Siwa Oasis by night bus (about 9 hours). So... how early should I buy my ticket? Same day at morning? Day before? Two to three days before?

http://www.siwaoasis.com/siwa_roads.html

Thanks for the link Crashdummy. We are looking at taking the train down to Luxor at about the same time.

I would buy the train tickets at least a day or so in advance. Buy them when you arrive at the train station and have it in hand. I don't know if this is the norm, but earlier this year, I hopped on a train to Aswan at Ramses station in Cairo, not one of the tourist sleepers. I was able to buy a ticket but it was standing room only for the first several hours of the journey, or sitting in the vestibule area between carriages. Many people were doing this.