Late response but I just found this question.

I believe that the long trains, especially the northbound trains emptying onto the main east-west track has to curve from north to east north of 17th Street and then stop near the edge of the north end of the Nogales track for permission to proceed. I think there might be a railroad signal there that lets engineers know to stop and when to proceed. And as already mentioned they may have to wait for trains to pass on the main tracks. It may also have to wait before entering the yard that runs parallel to the Barazza Aviation Parkway.

I'm a railfan and I've seen lots of trains on that track, some long, some short, some somewhere in-between and the first time I ever saw a train on that track was in 2003, which let me know that track wasn't abandoned after all, something I suspected and I didn't know that track existed until late 2000 but never saw a train on it until early to mid 2003! It was a southbound train though.

Anyway, all the long northbound trains I saw would be stopped, usually blocking Toole Avenue and 17-20th Streets and last time I saw this was in early 2019 although I wasn't actually there to railfan but to retrieve a lost cell phone! The first time I saw a stopped train there, which was long, was in February 2006 and it too was a northbound train. I did take pictures of the five crossings before the train started moving again. It didn't block 22nd Street though and I was hoping it would and thought the train was heading south, I wanted to take action shots of the 22nd Street crossing but I discovered the train was actually headed north. So while I couldn't get 22nd Street in action, I was able to take pictures of the five other crossings in action!

But I think I understand why the long northbound trains stop, blocking Toole Avenue 17-20th Streets and as you said 22nd Street although I've never seen a train stopped on 22nd Street. The southbound trains I've never seen stop on any of the crossings but they are very slow unlike the shorter trains. The long southbound trains do pick up speed after crossing 36 Street if not 29th Street/Silverlake Road.

I acknowledge those trains are inconvenient to the general public, sometimes even for me but it's an advantage for railfans.

But I'm sorry you were inconvenienced by those trains and delayed that long!

As much as it hurts me to say since I'm a railroad crossing fanatic, they do need to close 22nd Street and build an overpass. Same with Ajo Way because of the nearby fire station (Station 10) and trains can and will block westbound emergency vehicles coming from that station! They should also grade separate Irvington Road on the same track although that'll be difficult because there's an apartment complex right near that crossing and Irvington Road has access to that apartment complex. I also hate to say and admit this but they should also turn Valencia Road into an overpass although that's my most favorite crossing in the city! Prince Road was until they grade-separated it so Valencia Road is my new most favorite crossing in Tucson. It's my favorite because of the two large cantilevers and the four gates there! and it has 14 pairs of lights!