This train had the livery changed twice - first it had the "Olive-Green livery", separated by 2 yellow-lines between the upper & lower part of the windows & later on it was changed to "Maroon colour" on the MG.
This train was numbered as 6717/6718 when it was run on MG. It is now hauled by WAP 7 loco from Royapuram Loco Shed from Madurai to Chennai Egmore and via the same route.
Train number 12637 departs at 21:20 hours from Chennai Egmore and arrives at 6.15 hours at Madurai Junction. Train number 12638 from Madurai to Chennai starts at 20:35 Hours from Madurai and reaches Chennai Egmore by 05:35 Hours. The Train Also has a rake-sharing agreement with Rockfort Express as (16177/16178) from Chennai to Trichy.