It has been two decades since Southwest Symphony Orchestra celebrated the musical theater team of composer Richard Rodgers and librettist-lyricist Oscar Hammerstein II.

“An Afternoon of Rodgers & Hammerstein” on Sunday at Trinity Christian College's Ozinga Chapel Auditorium in Palos Heights features 65 orchestra members plus four soloists and 100 chorus members.

“Every year the orchestra tries to do a lighter concert. I was going through past programs and noticed 20 years ago pretty much to the month that we presented ‘An Evening of Rodgers & Hammerstein,' ” said David Crane, music director of Southwest Symphony Orchestra.

“The music is timeless. A lot of music comes and goes, but 100 years from now they'll be doing ‘The Sound of Music,' ‘Oklahoma!,' ‘The King and I,' ‘South Pacific' or ‘Carousel.' Those are the musicals from which this is drawn.

“The other one that's less known but, nevertheless, has some wonderful songs in it is ‘State Fair.' ”

Several guest performers were needed for the program.

The soloists are mezzo-soprano Samantha Attaguile, soprano Desiree Hassler, baritone Brad Jungwirth and tenor John Concepcion, a Flossmoor resident who produces the Opera Up Close series at Governors State University in University Park.

“With that ensemble, we can do any of the pieces from these musicals,” said Crane, who is also director of music ministries at Fair Oaks Presbyterian Church in Oak Park.

“In this particular concert there's around 25 selections from those six musicals I mentioned, so that gives us all the possibilities and pretty much the real deal. If you heard ‘The Sound of Music' 50 years ago on Broadway, it would have been this same orchestration and these same soloists and chorus.

“These are not arrangements of pieces. This is what the audience would have heard on Broadway at the time.”

Many more voices were required and will be provided by Grande Prairie Singers directed by Jo Rodenburg, of Frankfort, and the Moraine Chorale directed by Nicholas Thomas.

“It's what you need. You want a booming chorus. We'll have a lot of singers there,” said Crane about the Park Forest-based Grande Prairie Singers and the Palos Hills-based Moraine Chorale from Moraine Valley Community College.

“These choruses are a combination of seasoned singers and more singers who are just for the fun of it, so the combination is perfect for this community type of affair.”

Selections include “Climb Ev'ry Mountain” from “The Sound of Music,” “It's a Grand Night for Singing” from “State Fair,” “I Whistle a Happy Tune” from “The King and I,” the title song from “Oklahoma!” and “There Is Nothing Like a Dame” and “Younger Than Springtime” from “South Pacific.”

“If there's a favorite they have from each of these musicals, it most likely will be sung,” Crane said.

“It's one of those concerts where the melodies are, indeed, infectious. As much as it's a light concert, I consider music from these musicals akin to art song from Europe. It's really beautiful music, not just popular music.

“There's a universality. This is one of America's finest forms of art. I really have an affinity for musicals from a few decades ago.”

Southwest Symphony Orchestra, which closes its 2016-17 season with “Elizabeth Roe, Rachmaninoff & Sibelius” at 4 p.m. May 7, includes Evergreen Park, Oak Forest, Oak Lawn and Orland Park residents.

Jessi Virtusio is a freelance reporter.