A cappella has been used as the sole orchestration for original works of musical theater that have had commercial runs Off-Broadway (theaters in New York City with 99 to 500 seats) only four times. The first was Avenue X which opened on 28 January 1994 and ran for 77 performances. It was produced by Playwrights Horizons with book by John Jiler, music and lyrics by Ray Leslee. The musical style of the show's score was primarily Doo-Wop as the plot revolved around Doo-Wop group singers of the 1960s.
How many works of a cappella in musical theater have been successful in Off-Broadway productions?
four

Railroads have been an important method of transportation in Montana since the 1880s. Historically, the state was traversed by the main lines of three east-west transcontinental routes: the Milwaukee Road, the Great Northern, and the Northern Pacific. Today, the BNSF Railway is the state's largest railroad, its main transcontinental route incorporating the former Great Northern main line across the state. Montana RailLink, a privately held Class II railroad, operates former Northern Pacific trackage in western Montana.
How long have railroads been important since in Montana
1880s

The most catastrophic earthquakes we know of occurred in 31 BCE, 363, 749, and 1033 CE, that is every ca. 400 years on average. Destructive earthquakes leading to serious loss of life strike about every 80 years. While stringent construction regulations are currently in place and recently built structures are earthquake-safe, as of 2007[update] the majority of the buildings in Israel were older than these regulations and many public buildings as well as 50,000 residential buildings did not meet the new standards and were "expected to collapse" if exposed to a strong quake. Given the fragile political situation of the Middle East region and the presence there of major holy sites, a quake reaching magnitude 7 on the Richter scale could have dire consequences for world peace.
How often do earthquakes that lead to serious loss of life occur?
every 80 years