Has anyone taken the train from Christchurch to Greymouth? We are considering renting a car and driving,but would like to hear any comments about the train.

It's called the TranzAlpine (http://www.tranzscenic.co.nz/services/alpine.aspx). We've take it both ways. The route from Christchurch up toward Arthur's Pass is incredibly scenic, crossing back and forth on bridges and trestles over the steep narrow Waimakariri River gorge. The route from Arthur's Pass down to Greymouth is not as scenic, and at least a third of this portion is in a tunnel.

We have also driven the same route by car. You miss all of the scenic gorge, but you see much more open country instead. The route down to Greymouth is very steep, with hairpin switchbacks. Challenging driving, but very pretty.

Bottom line: Christchurch to Arthurs Pass is more scenic by train. Arthurs Pass to Greymouth is more scenic by car. If you are going to hire a car anyway to tour down the west coast, it may be more cost-effective just to hire the car in Christchurch and drive the whole way.

Yes, definitely take the train trip, it is most scenic.

Many thanks for your information!

Just got back from our honeymoon in NZ! Can't wait to go back.
We took the train to Greymouth and then rented a car from there and drove to Franz Josef for our 1st night. It was a good trip but the train trip ended up taking 6 hrs instead of 4 because one of the engines blew and we had to take it slow from Arthur's Pass and on (which is a steep decent as mentioned previously).

As ALF said, the 1st half is great, 2nd half...not so much but I do think it is worth the trip. The scenery is amazing and you don't have to worry about driving for the 1st 4 hrs as you'll likely end up doing a lot of driving throughout the rest of your trip.
Have fun!

The train trip is fabulous. Particularly the open carriage. You are out 'in amongst it' with the wind in your face and nothing between you and the scenery. Take a snug hat, scarf and gloves, even in Summer.

A wonderful experience. My husband and I never went back to our seats. We stayed in the open carriage the whole time, even in the tunnels.

They do close it for the big tunnel however, but we got out at Arthurs Pass.

One tip, the northern side of the train is reported to have the best scenery.

How does one go about booking a ticket on the TranzAlpine ? I found a number of tour operators that offer this, but the prices are fairly steep.

Is there anyway I can purchase a roundtrip ticket (Christchuch-Greymouth-Christchuch) directly without having to go through a tour ?

Try this:

http://www.tranzscenic.co.nz/inner/contactus.aspx