I'm auditioning for a youth orchestra (musicians are 14-28 years old). I must play two contrasting movements of a piece of my choice (no problem with that), some sight reading (I sure ain't good at that, but it's okay), and 3 orchestral excerpts. I was to audition tomorrow but the person in charge of the auditions forgot to tell me in advance (she called me today!) and she forgot sending me the orchestral excerpts (I didn't know which ones until today too)...so obviously I won't be passing the audition tomorrow, sight reading that kind of excerpts would be like suicide, but it will probably take place in 10 days. I'll receive the excerpts by mail in a few days, but now at least I know what I must expect.

I have to play part of the Hungarian March (the trombone theme at the end I guess), no big deal, I worked on it already in the past and I'm confident I can play it pretty good. I also have to play some excerpt from Mahler's 6th, 1st movement, and I'm wondering if I should expect something really difficult...?

Now here is where things get complicated. The third excerpt is from Schumann 3rd symphony, 4th movement and I was told it was the 1st trombone part, so I assume it will be the excerpt with the high Eb. Problem is, right now I can only go up comfortably to high Bb. How am I supposed to add a fourth to my high register within 10 days?

check your PM's.

I already have the sheet music for that particular excerpt, I'm just missing the exact bars which I must play in that one and the Hungarian march. And I don't have the sheet music for the Mahler. And yeah it was written for alto trombone, and orchestras often play that kind of repertoire with the original trombone section of one alto, one tenor and one bass.

Usually, when Hungarian March is on the list, you'll play the eight note soli section, as you guessed... but they often want the quarter note scale figures leading up to it (starting on the B natural).
As for getting your range up to the high eb for the Rhenish... there is no magic fix. Just do the best you can. If you miss it, it won't be the end of the world. You may not make principal chair, but you still have a chance of making the section.
Good luck!!

I don't expect to make first chair anyway, they're only missing a tenor and a bass, they already have 2 tenor trombones from previous seasons, and I know my high register isn't good enough for being first chair. However I'm surprised they ask me for that excerpt...but as you said, it's not the end of the world, I hope they won't judge me for one single note haha...

Well, I was wrong, they didn't have any trombonists from previous seasons, but anyway, I passed the audition tonight (earlier than expected), and it went really well. I missed the high Eb, but I played the Berlioz pretty good, as well as the Rimsky-Korsakov concerto, and I made 2nd chair. Finally it will be an all new trombone section, with the first trombonist who auditioned tonight too and the bass who had already auditioned. Our first concert will feature the overture from La Forza del Destino, Liszt's piano concerto no 1 and Bramhs' 1st symphony (can't wait to play that trombone choral heh). I'm very excited about all that, and it will be my first experience in a symphonic setup.

Anyway, thanks for your advice everyone.

well done on your audition
is there anyway u can email me Rimsky-Korsakov concerto as im trying to select pieces for an exam and thats one of my options
amy x x

Seriously? It's $7 at Hickey's. Just buy it.

Why is everyone looking for a free ride or a handout?

Erik, you just stole my line, I was about to write that haha! I bought it 8,95$ at my local music store, it's not like it's hard to find a cheap edition...