The liner notes for the Philip Jones Brass Ensemble recording of Pictures at an Exhibition contain a brief account of Elgar Howarth's arranging process. He wrote something about a particular instrument (maybe a D flugelhorn in the Old Castle) being a linchpin. I'd be more exact, but the LP is in a sealed container in my crawlspace - and I just like the word.
One of our regular trumpet players couldn't make the dates work for our first tour of the western United States in 2001. Dan Kuehn (Colorado Symphony) was one of our regular guys and his brother, Dave, happened to be available - what a gift! Among many other things, Dave was the principal trumpet of the Buffalo Philharmonic and he played almost everything on a 4 valve F trumpet.
I was hooked.
Actually, some of the trumpet players in town were early adopters of the Yamaha F/G trumpet and really liked it. But from a practical perspective, the F trumpet is less available than the E flat - that was the feedback when I started publishing a lot of music.
Nevertheless, the E flat trumpet is light and clear, but also retains some of the weight in the sound of longer trumpets. Because I view the entire range of a brass ensemble as a continuum from the lowest practical pitches to the highest, and since I like to orchestrate music that explores register and color, I like the way e flat trumpet makes a seamless transitions from one tessitura to another.
In the example above, you'll see and hear how I used the E flat both as a brilliant solo voice and also to transition to a lighter sound in a higher tessitura to piccolo. Typically, I won't use the e flat above a written A above the staff (sounding C), or below a written B below the staff (sounding D). Guidelines...not rules.
For me, E flat trumpet IS a linchpin.