|Locale||Tamil Nadu and Kerala|
|Current operator(s)||Southern Railway zone|
|Start||Trivandrum Central/Chennai Central|
|End||Chennai Central/Trivandrum Central|
|Distance travelled||909 km (565 mi)|
|Average journey time||15 hours 40 minutes|
|Train number(s)||12623 / 12624|
|Class(es)||First AC ,2 Tier AC ,3 Tier AC,Sleeper Class,General|
|Sleeping arrangements||Couchette car|
|Observation facilities||Large windows|
|Track gauge||1,676 mm (5 ft 6 in)|
|Electrification||25 kV AC 50 Hz|
|Operating speed||60 kilometres per hour (37 mph)|
Thiruvananthapuram mail (Trivandrum mail/Chennai mail (Madras Mail)) daily train running between Thiruvananthapuram and Chennai. It is one of the most prestigious trains of the Southern Railway zone of the Indian railways. This train runs via Kottayam.
The train was introduced in 1940 as No.19/20 Madras - Cochin Harbour Terminus Express and was later renamed as Madras - Cochin Harbour Terminus Mail .Diesel loco was given to this train in 1961.The train was later extended to Thiruvananthapuram Central when the rail link connecting to Trivandrum Central via Kottayam was completed.
As per the numbering system of the Indian Railways, the train has been currently assigned the number 12623 for the down direction (Chennai central - Trivandrum) and 12624 for the up direction (Trivandrum - Chennai central). In the downward direction, the train departs at 19.45 hours and reaches Trivandrum at 11.25 hours next day. In the upward direction, the train departs at 14.30 hours and reaches Chennai at 06.55 hours. Its timing is one of the most perfect timing in Kerala specially for people living between Kayamkulam JN (KYJ) and Ernakulam North(ERN). The Stoppages are more in this region and shows that the train is mainly meant for people residing in this region.
Trivandrum Mail is one of the very few trains in Kerala to have coaches of A/C first class. The train comprises 24 coaches - A/C First Class, A/C 2-Tier, A/C 3-tier, second class sleeper and general compartments.
In popular culture
No.20 Madras Mail which is a Malayalam movie released in 1990 has most of the scenes shot inside the moving Trivandrum Mail train.