GRAND RAPIDS TOWNSHIP, MI - The jam band Twiddle will perform with Railroad Earth at Frederik Meijer Gardens Amphitheater on Aug. 21 after moe. canceled its summer tour due to its lead singer's illness.

moe. canceled its tour last month after announcing singer Rob Derhak was diagnosed with oropharyngeal cancer.

With roots at Vermont's Castleton State University, Twiddle began its touring career in 2005. The foursome has composed an eclectic catalog spanning three studio albums of originals, in addition to many live releases.

Led by front-man Todd Sheaffer, the six-man Railroad Earth has been together and performing its bluegrass-influenced rock since 2001.

Tickets for the concert are still available at $41 for members and $43 for non-members, according to garden officials. The concert is scheduled for 6:30 p.m. with gates opening at 5:15 p.m..

Ticket holders who want a refund due to the lineup change may obtain refunds through Star Tickets by phone at 1-800-585-3737 or by email at customerservice@startickets.com. All refund requests must be submitted by Aug. 10.