Depends on the type of server system you are using. If you are using an old desktop converted into a server it should be very easy to carry/hold with two hands on its steel case. If you are using a larger scale server solution such as a server rack you can demount the rack from the cabinet and should then be able to carry/hold it with hands on each side. If you are trying to hold an entire server cabinet you might need multiple people to help carry/hold it or use some heavy machinery to help carry some of the weight such as a forklift truck or a winch attached to the roof.
Or are you asking how to setup a server?
In such a case you will need a computer system to act as the server which is attached to a network with your potential clients with a good upload rate. You will then need to self-build the POSIX server build of Simutrans (this version is not distributed pre-built) to act as your server. This version can then be started as a server from the command line, passing server configuration information as arguments. If the server is behind a NAT then appropriate port forwarding is required for clients outside the NAT to connect to it. The port used by the server for receiving TCP connections can be specified as part of the command line. Automated restarting and save backups can be done with some command line hackery.
The standard client can also be used as a server. This is done by starting it from the command line like the POSIX server build with the same arguments. This is not really suitable for remote servers with no window management system running. It also consumes more resources than the POSIX server build due to graphic support.