Do they make use of an API to get that information or "scrape" the Amtrak.com web site?
I thought about trying to write a program that can search for fares, but I wouldn't want to violate the TOU if I tried it:
Code of Conduct
While using the Site, Materials and/or Software, you agree not to:...
Use any robot, spider, site search/retrieval application or other manual or automatic device or process to retrieve, index, “data mine” or in any way reproduce or circumvent the navigational structure or presentation of the Site or its contents;
I suppose you would need a business relationship with Amtrak to develop an idea like that. Or is there some other API that I am not aware of?