SR some times adamant and dont take few things. They never added HCPV with TN and always added it to GT or other trains.
When rake standardization was announced none of major SR trains were standardized. TN they have requested with 23 coach LHB rake like Pandian/RF/Cholan/Nellai/Pothigai/Cheran/TVC Mail etc.
No TTZB from SR. They operate in their own wonderland.