Apparently they do offer a "Castle tour" line, which we discovered completely on accident. My cousin and I had been on the ride 3 times previously during our trip but had never taken our cameras through the que and wanted pictures. My uncle also wanted to view the que but knew he couldnt ride due to stomach surgery 3 weeks prior. So on our last night we headed over to Hogwarts with the sole purpose of viewing the que, we figured we go through the line(which was a posted wait time of 60 minutes) and my cousin and I would ride while my uncle ducked out through the chicken exit at the platform.
With this is in mind we were not going to bother with a locker, just hand him our bags before loading the ride. A TM stopped us and said, "You cant bring bags on the ride" and when we told him our plans he asked if we "really wanted to ride the ride or just see the castle" when we told him we didnt really care to ride again but figure we might as well after doing the line, he hearded us over to a staircase and pulled back the chain and told us to just go that way. Turns out it was the Castle Tour line which allowed us to wander the whole que(minus the outside greenhouses) at our lesiure and take pictures and soak it all in. It was great. Although I had been through the que 3 previous times we were able to really take the time to see all the effects, like the snow in the DADA room. We also were able to get some great pictures. Once we hit the loading area, they just ushered us to the side door and down the steps into Filches. Doing it this way we saw the whole que, while stopping a lot to absorb in under 20 minutes. There were a lot of other folks doing this very same thing as well.
So I would just ask a TM how you'd go about just touring the que line without riding. If you do the castle tour line it shouldnt take you long at all if you want to go through fast, or you can take as much time as you want to experience it.
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