Most of the time, an orchestra has three trombones, where it's two tenors and a bass.
The trombone is part of the brass section.
Horn, Trumpet, Trombone, and tuba.
In a symphony orchestra in the brass section there are usually 3 trombones in proportion with 4 horns, 2 trumpets and a bass instrument. ref The Oxford Companion to Music, orchestra, page 898.Most of the time, an orchestra uses three trombones, with two tenors and one bass.
Marching band or orchestra
In an orchestra they are Trumpet Horn (Formally French Horn) Trombone Tuba In a Brass/Silver band Cornet Trombone Euphonium Tuba
brass I think I could be wrong though
Trumpet, Trombone, Tuba, French Horn
trumpet, trombone, baritone, tuba, and french horn
Trumpet, Trombone, Tuba, French Horn
F horn, trumpet, trombone, and tuba.
Bass viole, Tuba, Trombone Cello, oboe, organ.
There are no trumpets in Urinetown: trombone and euphonium (1 player) only.