The limit of speed of trains is regulated in accordance with the classification of routes having particular type of track structure. The broad gauge (BG) lines on Indian Railways have been classified into six groups ‘A' to ‘E' on the basis of the future maximum permissible speed.
Group ‘A'- Speeds upto 160 kmph.
Group ‘B'-Speeds upto 130 kmph
Group ‘C'- Suburban section of Mumbai, Chennai, Delhi & Calcutta
Group ‘D' special & ‘D'- Speeds upto 110 kmph
Group ‘E'- Speeds upto 100 kmph.
The total expenditure on upgradation works for Delhi-Agra section including fencing at vulnerable locations is estimated to be Rs 16.35 crore.