This is how I see it. The EWR 756 flying is really some of the best flying in the entire system. You have domestic, Caribbean overnights, Hawaii South America and a ton of good Euro flying. Not to mention lots of 764 heavy wide body pay

. If they posted a vacancy guys based in IAD would jump all over it as they have in the past.
They need guys on the 76T/756 and they don't need guys to bid off the 320/777/737 to fly it because it would cause to many training events. So they pull a seniority end around. Put out a vacancy for EWR 76T garbage flying that nobody wants. Fill it with new hires and then give all the new hires 4 days of differences training and make them a 756 pilot.
New Hires will not be getting 756 anytime soon because vacancies for that fleet will not go unfilled however the 76T will continue to go unfilled until the fleets are merged in late 2015 (supposedly).
A seniority F job that the company loves and the union approved.