Can't seeem to find the luggage restrictions. We plan on having alot of stuff as we will be coming from the US for 3 weeks. Anyone know if they are strict with the baggage weight and number of bags?

Here is an excerpt from the Tranzscenic site

http://www.tranzscenic.co.nz/tandc.aspx

11.3 Checked Baggage allowance
(a) A Passenger is entitled to carriage free of charge on any Passenger Rail service, 2 items per person, maximum weight 20kg per item. Size must be no more than 200 linear cm (height plus length plus width).
(b) Baggage between 20 to 30kg: we require your assistance in loading and unloading your bag from the baggage van or you can repack into bags provided to meet the 20kg per item limit.
(c) Baggage over 30kg: will not be accepted, your baggage will need to be repacked into bags provided to meet the 20kg per item limit.
(d) Extra Baggage (eg surfboards, bicycles) will be carried only if space is available at a cost of $10 per item per service. Non-personal items such as household equipment, crates of fruit etc, will be charged as extra baggage and carried only if space is available and can be easily lifted and stored. Hazardous or offensive items will be rejected at check-in.
(e) No Checked Baggage may be carried on a Suburban Carrier Service except at the absolute discretion of the Train Manager.

We took the TA in 2005. As I remember, we took our bags to the last (luggage)car, and they simply put every bag from everybody in it. No questions asked.

we just took the train, and loaded up the luggage in the last car. no one seemed to care how much we had.

It isn't difficult to travel for 3 weeks in a 21" rollaboard. It does require doing some laundry but that is a great way to meet locals. I would think that you would be quite sick of lugging much more after a few days.

For tips on traveling with less:

http://www.onebag.com/