Hallo Joachim,
leider, leider verfüge ich (noch) nicht über eigene Erfahrungen mit der TAZARA. Ist aber ein langgehegter Reisetraum von mir.
Vielleicht hilft dir dieser Link:
How to buy tickets for journeys starting in Dar es Salaam...
You cannot buy tickets online, you should buy them at the station or by phone. Call Dar Es Salaam ticket office on +255 22 26 2191 for westbound journeys, or call the station master at Dar on +255 78 7099 064, reserve by phone and collect and pay for tickets when you get there.
An email from Tazara customer relations also suggests that bookings can be made on any of the following numbers: +255 715469239 (confirmed as working by one seat 61 correspondent), +255 784345492, +255 754260988 or +255 784454510. They will make your booking and you pay and collect tickets at the station later. Please let me know if one of these works for you.
Alternatively, you can buy tickets before you get to Tanzania by contacting a good local travel agency. Try emailing or calling
zanzibarmagic.com, +255 777 844417, +255 768 242224. Booking opens 1 month in advance of departure. Feedback on ticket buying would be appreciated.
How to buy tickets Zambian Railways...
It's easiest to by tickets when you get there, at the station. However, you could also try calling the departure station, using these numbers (feedback would be appreciated):
Lusaka +260 211 228023
Livingstone +260 213 321001
Kabwe +260 215 224027
Herzliche Grüße
Marina