vo ye check krna chahte hain ki kya 100mps track par 100mps se zyada ki speed se train daur sakti hai... vo delhi-mumbai main line par islye test ni kr rhe coz agar koi problem aaya to uss line ko kuch ghanto ke liye bnd krna pdega..... aur vo boht busy route hai.... that's why they are testing first on a low priority route