the train station is about 2 kilometers from the city center--Bell Tower.

It is possible to climb this mountain in this time of the year, just bring some warm clothes.

The subway of Xian is still under construction, the best way to Wild Goose Pagoda and then terra cotta warriors are taking bus, you can take Bus 306 at the railway Station, it goes directly to Terra Cotta Worriors. If you are staying in the city center, the best way to Terra Cotta Worriors is taking bus and the best way to Wild Goose Pagoda is taking taxi.

You can check at Xian Tours(https://www.travelchinaguide.com/package/xian.htm) for more destinations and itineraries suggested.

Ms. Anke,
I have to say that Mr. Michael is correct but would like to add.
Be prepare because language is a big problem. I came back from China in September 2010 and I stay 7 days in Xi'an very few people speak english.
The public transportation is great but don't expect to get any help, simply no one will understand you.
Get some guide or organized tour before you go.
Don't understand me wrong people are very nice and very sweet but you will be wasting lots of time on you own.
Enjoy your trip!

Hello, Ms Anke
I am Terry in xi'an China The train station is very close to the center of the city, the distance depends on where your hotel is. It is not wise to clime the mountain at this time of the year, for it is really cold here. One day is enough, although a little short.
Metro has not been used. Lots of bus can take you to the wild goose pagoda. 0.1 dollars is enough. it will take you 2 or 3 dollars to go to terra cotta, it takes 40 minutes or more to go there by bus. Bussis is not convenient for non-chinese speaking people, you had better to know which bus you will take before you get on it.
Good luck for your holiday here.