We salute Gadling for spotlighting a new website, Urbanrail.net, that offers the world's most thorough online guide to the public rail systems. Gadling also points out a feature that's great for budget-conscious travelers:
A section on Practical Information includes the operating hours and the costs. More importantly, it lists various passes which can help make your visit all the more economical. For example, a single ticket on the Oslo T-Bane costs 20 Norwegian Krone. Yet, a 24-hour "Dagskort" pass costs just 60 NOK--a much better deal if you plan on taking many rides throughout the day.