A small change to your list sir (possibly). As you'd probably remember, in the links I shared with you earlier, there was a day time train too between MAS-Beypore (later Mangalore) since 1862 (As you can see in this extract from 1879). Earlier, I was of the opinion that this was the predecessor of the present day Intercity (Lalbagh's RSA partner). As I mentioned in my earlier post regarding the Bangalore mail being introduced as a separate service in 1908, the ICE was also started in 1908. At the time, I assumed that the daytime train was discontinued or changed into some random passenger train that gradually vanished.
I had the chance to dig through some old...
more...

Bradshaws and documents, and I see that the day time train from 1862 was still operational even after the ICE was introduced, but running as a passenger instead of an express. You can see this in the 1931 Bradshaw as the 706 Passenger from Mangalore to Madras, which ran combined with the 15 Bangalore-Madras passenger between JTJ-MAS. The same train, with slight changes in timings is continuously present in all the timetables since then, running between Banglaore-Madras as the 95/96 passenger at least since 1977 (the portion to Mangalore having been discontinued at some point). This train was operational even in 1999 with the same train number. Today, this train is running as the SBC-AJJ passenger ( having been short terminated at AJJ sometime after 2000).
So, both sisters have been continuously serving the route for the past 155 years. while one retained some part of it's grandeur by still running as a mail train, and being upgraded as a super-fast, it's sister train, once the faster of the two, and the original mail carrier on the route (In the initial years, night carriage of mails was not allowed. It was only allowed some time between 1864-1868) lives on silently as a nondescript passenger, running between different destinations.