If you look at NTES it is clearly seen that train is always on time till DMM. SWR always receives this train late at SBC. I guess pf constraints in SBC , plus huge traffic around that time plays a major part. Most of the time it is received only after 11pm. It has got just 2 hour layover period at CBE. Any delay from SBC results in late arival at CBE and subsequent late departure from CBE. Moreover the single line section between Salem-SBC also plays a part in delay as there is no time to make up.