its meter guage. I travelled in 2004 frm ooty to mtp. First it was hauled by a diesel loco til coonoor. Then steam engine (I guess it was steam loco as water was being filled in loco at coonoor) hauled it til mtp. It ran very slow til it descended the gradient and reached ground level after which it ran at good speed till mtp, a distance of abt 8 kms.