We're going to start testing a few raid encounters on all Beta servers this Sunday, October 17 at 13:00 PDT. Two encounters will be tested:

Omnitron Defense System in Blackwing Descent
Halfus Wyrmbreaker in The Bastion of Twilight

Blackwing Descent is a raid zone with an entrance located along the side of Blackrock Mountain.
The Bastion of Twilight's entrance is located within Twilight Highlands.

Since these are the beta realms, this schedule is subject to change at a moment's notice due to bugs and server issues. More raid tests will be occurring over the next few weeks.

There was an issue with the EU queue that was supposed to be resolved last night. Have you tried today?

Update on the EU Queues:

They should be better now, please try again.

I'm pestering people about this, sorry for the delays on copying. This won't be the only opportunity to test these two encounters.