You may contact the initiators, Wouter, Jan Dirk and Sing via email: info [at] tangotrain.com.
But you may also catch them with a Facebook PM.
Please note that there is no passe-partout available, since all milongas & workshops are organised by each individual host. So contact them directly.
On the list of milongas you will find webaddresses and telephonenumbers of each.
You can also check each facebookevent for more details.
There is one facebookevent
for the entire TangoTrain, where all FB events are listed.
And you may contact others and ask for (and offer) rides, couches, and what have you at the Facebook TangoTrain Group