From #openttdcoop wiki
Our community #openttdcoop consists of three main servers.
All persons with administrative rights should have a closer look to the Server Administration Guide
If you heard of #openttdcoop and would like to make the first steps toward a membership in our community, simply read what you have to do at Membership and Public_Server. Feel free to join our community and play on our Public_Server.
rcon on The Public Server is granted to every member of #openttdcoop and some players, depending upon need.
Playing access (password) is granted to all our members (see Membership for further details) and selected individuals who have proven on our Public Server that they are decent builders and usually know what they do.
rcon on the ProZone is granted to every member of #openttdcoop.
The stable welcome server is a openttdcoop playground server without a password and less restrictive rules than the other servers.
rcon to this server has every member of #openttdcoop and is passed on to teams in need of a server.
Sometimes, we need a server for testing various patches and settings in order to support ongoing development or simply to prepare for upcoming games.
rcon on this Server is granted to every member of #openttdcoop and trusted other persons.