Book excerpt: Revitalizing railways as a major sustainable transport mode in modern societies faces many issues and challenges. This in-depth overview places the importance of railways in the wider context of comprehensive sustainability, which encompasses sustainable development, social and economic equity and community livability. Some scholars have described the 21st century as a period of renaissance for railways and suggest this transport mode can fulfil people's desire for high mobility with low negative environmental, social, economic and financial impacts. In light of these new expectations for railways, in both passenger and freight transport worldwide, this book offers the latest research insights on the renewed interest about railway expansions and their wide-ranging environmental, socio-economic and even political implications.