In 1945, Bill Monroe brought banjo expert Earl Scruggs into his Blue Grass Boys backing band (which also featured guitarist Lester Flatt) and in essence created the musical genre which would become known as Bluegrass. Through the 25 or so years that followed, Bluegrass was primarily played by old men wearing matching hats and suits who all stuck to a strict definition of what it meant to play the music. Then in 1971 Sam Bush and Courtney Johnson formed Newgrass Revival, a rag-tag bunch of longhairs playing in the traditional bluegrass ensemble who liked covering rock ‘n’ roll, protest and even reggae songs, and who stretched the genre beyond its somewhat rigid confines. The Newgrass spirit was further developed by artists like John Hartford, J.D. Crowe and The New South and Seldom Scene. The sound would later be transformed even further when Colorado bands like Leftover Salmon and The String Cheese Incident took the instrumentation of bluegrass, added rock ‘n’ roll drums and began to improvise in new and inventive ways. New Jersey-based Railroad Earth, coming to The Waiting Room on Monday, falls into the direct lineage of these bands. “One thing people have to remember,” says Railroad Earth co-founder and mandolin player John Skehan, “and bluegrass purists can be pretty strict on what they consider bluegrass, but what Bill Monroe was doing was pretty revolutionary in terms of country music. I guess, where we fall in with that, and I’m a big fan of Bill Monroe, would be that I’ve always loved the bluegrass ensemble; the mandolin, banjo, guitar and fiddle. It seemed like adding drums, an element of rock ‘n’ roll, just seemed logical.” Railroad Earth came to fruition as a band during the early part of 2001 and took the name from a Jack Kerouac short story called “October in The Railroad Earth.” The current lineup features Skehan, vocalist/guitarist Todd Sheaffer, vocalist/violinist Tim Carbone, multi-instrumentalist Andy Goessling, drummer Carey Harmon and bassist Andrew Altman. The band played a couple of gigs in and around New Jersey and Pennsylvania and quickly found a manager to come on board. That summer the band was given a spot at the prestigious Telluride Bluegrass Festival (this was its 10th show ever), a tough nut to crack and a testament to the band’s astute musical proficiency. The band’s live, vigorous tenacity and its penchant for musical exploration quickly landed Railroad Earth a devoted following who now refer to themselves as the “hobos.” The band has become a festival favorite and this summer will play Telluride, Floydfest and Bonaroo among others. And while Railroad Earth’s live show is a musical spectacle of gorgeous harmonies, pistol-whipped picking and musical interplay, the band also has a recorded canon that stands among the best bluegrass-influenced acts going today. The band currently has six long-players to its credit, including two on stalwart bluegrass label Sugar Hill and two on String Cheese’s imprint SCI Fidelity. The most recent, 2010’s self-titled release, is the band’s most developed to date. The sound stays true to the band’s Newgrass roots but also has a classic country rock feel to much of the music. Tracks like the sprawling 11-minute “Spring-Heeled Jack” find the band drawing out the compositions in familiar fashion and in a new development. “Jupiter & The 119” could find itself on alternative radio station playlists. Longtime fans will find Railroad Earth staying true to its top-shelf songwriting, impeccable musicianship and soaring harmonies. “We were going for certainly a more production-oriented record on the new one,” Skehan says. “Having come from Amen Corner, which was basically a home recording experiment in a big old farmhouse where we just rolled the tape while we played and jammed. It seemed more logical to go for a production aspect on this one. All the songs are new to the band’s repertoire except one. This one was definitely more of a construction piece. The process allowed us to do a lot more vocal work. Vocals have always been an important part of the band since its first record. On this one we really utilized everybody’s voice in some aspect.” Railroad Earth plays Slowdown, 729 N 14 St., on Monday, March 28 at 8 p.m. The all-ages show will start at 8 p.m., Whitewater Ramble will open and tickets are $20 in advance and $25 day of. For more info visit radkadillac.com.