I think it's still a work in progress, and they are just using the R32 sounds as a place holder. Being this is the same team that made both the R32,38 and R46 (and others), I think it's safe to say they know what an R44 sounds like. In fact the sounds of the OpenBVE R46 are very close to what the R44 sounds like, especially the brake release sounds at least Pre overhaul. Having rode the R44 everyday back in the 70's on the D line.