New Delhi - Mumbai Central is 'A' class line allowing speed 130 to 160 Kmph.
This excludes suburban areas where there is no such limit.
New Delhi-Mathura - 100 Km/h
Mathura-Kota-Ratlam- 130 km/h
Ratlam-Vadodara-...
more... 100 to 120 km/h
Vadodara-Surat-Virar- 120 km/h.
In between Mathura-Kota section train attains max. speed.