Hearing a bluegrass song with lyrics about hills and trains is unremarkable. Hearing a bluegrass song about “the hills of Jersey City” and a train that’s probably a subway is remarkable indeed. If the cardinal rule of Americana is sing-about-what-you-know authenticity, then the Demolition String Band certainly scores on that qualification. The Hoboken quartet has strong musical roots in bluegrass traditions – leader Elena Skye studied mandolin with Jethro Burns – but those roots are shot through with plenty of rock ‘n’ roll electricity. Correlations could be drawn to towering roots/punk bands like Lone Justice and X, but Skye’s twang of a voice and the chugging, old-school instrumentation lands these guys firmly on the “roots” side of the equation. Subways and landfills aren’t the sole lyrical territory; there are also the requisite “drinking and thinking about you” lines. But the energetic and full-bodied approach the DSB takes keeps any of it from getting too precious or predictable.