Two friends of mine told me they were taking the train yesterday from Yerevan, which would travel overnight, and arrive today in Tbilisi.
Unfortunately they didn't tell me what time the train is expected to arrive!
Now official train timetables in this part of the world seem to be hard to find at least if you can only search in English. Searching generally I find somewhat consistent answers in forums on travelling in the opposite direction from Georgia to Armenia, but the information for this direction seems to be out of date. I am told trains leave from Yerevan on even days of the month but I'm not sure this is current as others have told me there is a day train and a night train and the most current online answer I can find, from September 2011, even states the train is not overnight:
The last option can be the train that leaves Yerevan at 3.00 pm and reaches Tbilisi at 11.00 pm.
So what is the current timetable for trains from Yerevan Armenia to Tbilisi Georgia as of March 2012?