Not exactly MS-SA-MS, but a portion of it does have an interesting RSA like the LD-MRJ passenger you posted about. The Mettur Dam-MS slip coaches ( 1 SLR, 1GS and 1 sleeper ) run from Mettur dam to Salem Junction as a part of the ED- Mettur dam passenger, and from there as an express to MS and later through RSA, as a superfast train to Dadar. And when running with the Erode passenger, it'll be a CR train, running as a part of an SR train and ( I'm not sure about this one) if the coaches belong to CR only, then when running with the Erode passenger, it'll also be a rake consisting of CR and SR mix coaches.