For Railgun you can use a separate server or run it on a web server. We recommend to have 1 Railgun per data center, but it depends on how many domains and how often dynamic content is updated.
Our Railgun installation and configuration guide includes specific system requirements and supported operating systems for Railgun. We also have a step by step video guide on how to install and configure Railgun.
During the Railgun installation process you will need to use a unique Railgun token which is generated once you add a new Railgun under Partner Portal "Railgun" tab.