Here are my favorite links

Railfan Sites

trainorders.com
railroadnews.net
trainweb.com
Robin Bowers Train Page
Elizabeth Guenzler Train Page.
Steve Grande Website

Steam links

Santa Fe 3751
Friends of the 261
Friends of the 4449
Steam Train Diary
Railway Preservation News
Union Pacific's Steam page

Passenger Trains

United States:

Amtrak

Rail sites for traveling in Canada:

Via Rail
Canadian Passenger Rail Service
Algoma Central Railway
Ontario Northland

Others

Jeff Hartmann Art and Railroad page