How can the police track you with a warrant?

By using the internet.

Can you explain exactly what you are asking? A warrant can be a number of things. It can be document that is used to arrest someone. It can also be a document used to obtain evidence about someone. So you really need to clarify what you mean.

Cops use the last known address, or arrest you when they run your name after an encounter with them. They may even check the addresses of friends, relatives, or employers if they want you bad enough.