Train From Beijing or Shanghai To/From Lhasa.....

I don't think that was ever a tag for Tibet.

Anyways, the train from Beijing or Shanghai (or Guangzhou) to Lhasa takes 2 days. The first day is getting from any of those places to get to Xining in Qinghai Province; which is why many people only train from Xining instead.

Tickets tend to be harder to get for trains heading INTO Tibet compared to getting out from there. Consider flying in and taking the train out from Lhasa to Xining instead.

You also need to make sure that westerners are being permitted entry to Tibet, and find out what the current permit requirements are. You can't just get on a train to Tibet like you can to, say, Xi'an.

Thanks. I guess I will need to contact a Chinese tourist agency if I want tickets in advance. Has anyone used one that they can recommend?

You need an agent specialized in Tibet travel and can get you the Tibet Tourism Bureau (TTB) permit, like you disk last time getting to Lhasa. They can get you he train tickets as well.

We made our arrangements with a travel agent after we arrived in Chengdu when we flew to Tibet several years ago. Since we are only interested in the train ride, I would not want to fly to Beijing or Shanghai without having secured train tickets. Maybe we'll reconsider.

You need to find and work with an agent before hand.