Aisa nahin hai, maksi-guna section pe bhi trains bahut kam hai par wo speed heaven nahi hai :) In addition to traffic density, speed largely depends on "track condition/soil condition". A well-built track in good condition will definitely provide high speeds, and much better when it is double-line electric. However a poorly built track with loose soil(Dewas-Maksi track in MP) will never provide good speeds, lots of safety concerns there...