We introduce a new reversible fragmentating coagulating process of particles with variable sizes interacting on the real line. The construction is based on a new class of measures on the set of real increasing functions which serve as reference measures for a family of naturally associated Dirichlet forms. The process is an infinite dimensional version of sticky reflecting dynamics on simplices. Among other things we identify the intrinsic metric which allows to prove a Varadhan formula with the Wasserstein metric for the associated measure valued diffusion. Joint work with Vitalii Konarovskyi.