After finishing the Railroad quest (Deacon was my companion at the time) I fast traveled from the top of the Mass Fusion Building but Deacon was no where to be found. Here's a link to the topic I made that explains:

http://www.gamesas.com/topic/1587476-unable-to-find-deacon/

I ended up using the console and here is what I found:

http://images.akamai.steamusercontent.com/ugc/608352205830545108/3B98CF2B4707685E42C26BD7C52000ADEE83CA73/